Easy Lemon Drizzle Flapjacks - Lemon Oat Bars Recipe

What Makes This Recipe Great!

Great for Beginners – My lemon flapjack recipe is easy to make with the right technique and uses simple ingredients.

Freezer Friendly – Leave the lemon topping off and freeze them for up to 3 months.

An Energy Boost – These snack bars are full of oats giving you a burst of energy and are full of fibre.

About This Recipe – In More Detail

That fresh taste of lemon always reminds me of summer. Just like this Lemon and Blueberry Drizzle Cake, I tend to think of picnics in the sun while enjoying these.

But, of course, you can enjoy these any time of the year while bringing those lemon flavours into your kitchen in a new way.

I’ve packed our lemon oat bars with lemon zest, lemon extract and combined lemon juice with icing sugar for the drizzle on top. My oaty bars are packed with porridge oats and held together with a mixture of golden syrup, sugar and butter.

If you use the right technique, you’ll create delicious breakfast bars that don’t fall apart. Check out our Chocolate Flapjacks Recipe where I talk about the key steps for creating flapjacks that don’t crumble upon slicing. And if you love the tastes of classic British recipes, try these Bakewell Flapjacks too!

Equipment Needed

Medium Saucepan: A medium or large saucepan is used to melt and combine the butter, golden syrup, and light brown sugar for the flapjack mixture.
Mixing Bowl: A large bowl is needed to hold the ingredients for mixing. You’ll also need a small bowl to mix up the lemon drizzle icing at the end.
Baking Tin: A 20cm (8 inch) square baking tin, lined with baking paper, is used to shape and bake the flapjack mixture. If you do not have this specific size, use one that is similar. You can also use a rectangle baking tin too.
Spatula, Palette knife or Large Spoon: Used for pressing down the flapjack mixture evenly into the baking tin.
Wire Rack: After baking, a wire cooling rack can be used to cool the flapjacks in the tin to room temperature.
Sharp Knife: A sharp knife is necessary for slicing the set flapjacks into portions.
Fork: A fork is used to drizzle the lemon icing over the flapjacks.
Measuring Scales and Measuring Spoons: Needed for precise amounts of the ingredients.

Ingredients

Porridge Oats: The main ingredient for our simple traybake.
Unsalted Butter: Melted along with golden syrup and brown sugar to create a rich and binding mixture for the flapjacks.
Golden Syrup: Adds sweetness and stickiness to the flapjack mixture, contributing to its texture and flavour.
Light Brown Soft Sugar: Sweetens the flapjack mixture and combines with butter and golden syrup for a deliciously caramelised taste.
Lemon Zest: Infuses the flapjacks with citrusy aroma and flavour, enhancing the overall taste.
Lemon Juice: Used in both the flapjack mixture and the glaze, providing a tangy and refreshing lemon flavour.
Icing Sugar: Mixed with lemon juice to create a sweet and zesty glaze for drizzling over the cooled flapjacks.

Additions and Substitutions

Substitutions:

Porridge Oats: Rolled oats or quick oats can be used as a substitute for porridge oats. Be aware that using bigger oats can affect the texture of the finished lemon bars and make them crumbly and more likely to fall apart on slicing.
Golden Syrup: Honey or maple syrup can be used as an alternative sweetener. If you are outside of the United Kingdom it can be a little difficult to find this ingredient. However, you can make your own golden syrup with only a few ingredients.
Light Brown Soft Sugar: Dark brown sugar or caster sugar can be used as a substitute. However, the flavour of the finished flapjacks may be slightly different.
Lemon Extract: You can use a concentrated lemon oil flavouring in place of lemon juice in the flapjacks (not the glaze) to really match the taste of a lemon drizzle cake. However, only add 1 tsp as the flavour is stronger than lemon juice.

Additions:

Nuts: Chopped nuts such as almonds, walnuts, or pecans can be added to the flapjack mixture for extra crunch and flavour. Be mindful of any additions that you make. Adding too much may affect the ability of the flapjacks to hold their shape once baked and sliced.
Dried Fruits: Raisins, cranberries or dried blueberries can be added to enhance the sweetness and texture.
Chocolate Chips: For a sweet and indulgent twist, chocolate chips can be mixed into the flapjack batter.
Salt: Adding a little pinch of salt can help season the flapjacks and bring out their flavour, but it isn’t a necessity.
Lemon Curd: If you want even more lemon elements, try sandwiching a layer of lemon curd between the flapjack mixture. Place half of the mixture into the baking tin, spread in the lemon curd and top with the remaining flapjack mix before baking.

Step-By-Step Guide – How To Make This Lemon Drizzle Flapjacks Recipe

Step 1: Preheat the Oven

Preheat your oven to 150°C (302°F).

Step 2: Prepare Wet Ingredients

In a medium-sized saucepan, combine unsalted butter, golden syrup, 1tbsp lemon juice, and light brown sugar.
Heat gently, over low to medium heat, stirring until melted. Set aside to cool slightly.

A saucepan with the ingredients inside ready for melting.

A saucepan with the ingredients for melting inside it. A hand is pouring lemon juice into the saucepan.

Step 3: Mix with Oats

Place porridge oats into a large mixing bowl.
Add lemon zest, ensuring even distribution.
Add the melted butter mixture to the oats, mixing well until all oats are covered.

A glass bowl with the oats and melted ingredients poured in but not mixed together.

A hand is using a blue spatula to mix the flapjack ingredients together in a glass bowl.

Step 4: Line and Press

Line a 20cm (8 inch) square baking tin with baking paper, leaving a little overhang, and lightly grease.
Transfer the flapjack mixture into the lined baking tin, pressing it down firmly and evenly using a spatula or the back of a spoon.

Step 5: Bake

Bake in the oven for 30 minutes.

Step 6: Cool in Tin

Remove the flapjacks from the oven; they may appear slightly soft at this stage but should be golden brown in colour.
Allow them to harden and cool to room temperature in the baking tin.

A hand is using a blue spatula to press the flapjack ingredients down firmly in a lined baking tin.

A hand is holding a baking tin with the cooked flapjack slab inside.

Step 7: Lift and Set on Rack

Once cooled and firm, lift the flapjacks out of the tin using the overhanging grease-proof paper. Remove the paper and place the cooled flapjack slab on a wire rack.

Step 8: Prepare Lemon Glaze

Mix 1.5 tbsp lemon juice with the icing sugar to create a thick lemon icing. You may need to adjust the amounts slightly to create an icing that drizzles without being too runny.

A hand is using a small fork to stir the glaze ingredients in a white bowl.

Two hands are drizzling the lemon flapjack slab with the lemon glaze from a white bowl.

Step 9: Drizzle and Set

Drizzle the flapjacks with the lemon icing using a fork and allow it to set.

Step 10: Slice and Store

Once the lemon icing has set, use a sharp knife to slice the flapjacks into portions.
Store in an airtight container, either in single layers or with baking paper between each layer.

A hand is holding a slice of lemon drizzle flapjack up to the camera. In the background there are more slices laid in a random pattern with decorative items around them.

FAQ

Can I double the ingredients in this lemon drizzle flapjack recipe for a larger batch?

Yes, you can double the ingredients, but ensure your baking tin is appropriately sized, and you may need to adjust the baking time slightly.

Why do they seem soft when first removed from the oven?

The initial softness of the flapjacks mixture is normal. They’ll firm up as they cool.

Can I substitute golden syrup with something else?

You can substitute golden syrup with honey. However, you may find that your flapjacks don’t hold together so well. If you cannot find golden syrup at your local supermarket, you can always make your own golden syrup substitute at home.

Pro Tips and Guidance

Even Mixing: Thoroughly mix the lemon zest with the porridge oats to distribute the citrus flavour evenly. This ensures a balanced lemony taste in every bite.
Pressing Down Firmly: When transferring the flapjack mixture into the baking tin, press it down firmly and evenly. This helps in creating a cohesive and well-structured flapjack that holds together when sliced.
Baking Time: Keep an eye on the baking time to achieve the desired texture. The flapjacks may seem soft when initially removed from the oven, but they will firm up as they cool.
Cooling Process: Allow the flapjacks to cool completely in the baking tin before attempting to lift them out. This ensures they set properly and are easier to slice into neat portions.
Lemon Glaze Thickness: Adjust the thickness of the lemon icing by adding more or less icing sugar to achieve the desired consistency. A slightly thicker glaze will offer better drizzling control.

Storage

Storage: Store the flapjacks in an airtight container at room temperature for up to one week. For longer shelf life, refrigerate them, ensuring they are well-sealed to prevent moisture absorption.

Freezing: While flapjacks can be frozen, I recommend to freeze them without the lemon icing. Wrap individual portions in plastic wrap and place them in a freezer-safe container. This helps preserve the texture and flavour. Once thawed, drizzle with fresh lemon icing. You can keep them in the freezer for up to 3 months.

Defrosting: To defrost frozen flapjacks, transfer them to the fridge overnight and add the lemon icing after thawing for the best taste and texture.