Flapjack Recipe | Classic British Oat Flapjacks

Name: Flapjacks
Prep time: 10 min
Cook time: 20 min
Total time: 30 min
Yield: 16
Cuisine: British
Ingredients: 250 g Unsalted Butter; 150 g Golden Syrup, (150g is approximately 4 tbsp - use a warmed spoon for easier measuring); 150 g Light Soft Brown Sugar; 350 g Rolled Oats, (not instant oats - they produce a mushy flapjack); 0.5 tsp Fine Salt; 100 g Dark Chocolate Chips or Chunks; 80 g Dried Cranberries or Raisins; 50 g Mixed Seeds, (pumpkin, sunflower, sesame); 50 g Desiccated Coconut; 1 tsp Ground Cinnamon or Mixed Spice; 150 g Dark, Milk, or White Chocolate, melted, spread over the cooled flapjacks

British flapjacks are one of the finest things to come out of a home oven - thick, chewy, golden bars of rolled oats bound together with butter, golden syrup, and brown sugar, baked until just set with a slight softness in the centre that firms up as they cool into something deeply satisfying. They're not the granola bars of American cooking; they're something altogether richer, stickier, and more indulgent, and they've been a staple of British home baking for generations.

The key to a great flapjack lies entirely in the bake - and specifically in knowing when to stop. A flapjack baked until it looks done in the oven will be hard and brittle when cool; one pulled out while it still looks slightly underdone in the centre will set to a chewy, yielding perfection. Golden syrup is the defining ingredient - it provides sweetness, chew, and that characteristic sticky, caramelised quality that no other sweetener replicates. Don't be tempted to substitute it.

This recipe produces classic British flapjacks - no additions, no variations, just the definitive version. Optional additions including chocolate, dried fruit, and seeds are included for those who want to take them further. They keep brilliantly for a week, pack well in lunchboxes, freeze well, and are one of the most reliably crowd-pleasing bakes on the site. All ingredients are standard supermarket staples.

Ingredients

For the flapjacks

250 g Unsalted Butter
150 g Golden Syrup , (150g is approximately 4 tbsp - use a warmed spoon for easier measuring)
150 g Light Soft Brown Sugar
350 g Rolled Oats , (not instant oats - they produce a mushy flapjack)
0.5 tsp Fine Salt

Optional additions (fold in with the oats)

100 g Dark Chocolate Chips or Chunks
80 g Dried Cranberries or Raisins
50 g Mixed Seeds , (pumpkin, sunflower, sesame)
50 g Desiccated Coconut
1 tsp Ground Cinnamon or Mixed Spice

Optional chocolate topping

150 g Dark, Milk, or White Chocolate , melted, spread over the cooled flapjacks

Method

Preheat your oven to 160°C fan / 180°C conventional / Gas Mark 4. Grease and line a 20x20cm square baking tin with baking paper, leaving overhang on two sides for easy lifting.
Place the butter, golden syrup, and brown sugar in a large saucepan over a medium-low heat. Stir occasionally until the butter has melted and the sugar has dissolved - about 3–4 mins. Don't let the mixture boil.

Tip: Warming the golden syrup measuring spoon in hot water before use makes the syrup slide off cleanly rather than sticking. Alternatively, measure directly into the pan on kitchen scales - far easier than trying to spoon it accurately.
Remove from the heat. Add the rolled oats and salt and stir thoroughly until every oat is completely coated in the butter and syrup mixture. Fold in any optional additions if using.
Tip the mixture into the prepared tin and press down very firmly and evenly with the back of a spoon or the flat base of a glass - press hard, working methodically across the whole surface. A firmly pressed flapjack holds together when cut; a loosely pressed one crumbles.

Tip: Pressing the mixture down firmly is the most important step for flapjacks that hold together cleanly. Take your time - press across the entire surface multiple times until the mixture is compact and level. The firmer the better.
Bake for 18–22 mins until the edges are deep golden and the centre still looks slightly pale and underdone. The flapjack will look soft and almost unset across the middle - this is correct.

Tip: The timing is everything with flapjacks. The centre should look underdone when you pull them from the oven - it will firm up considerably as it cools. Baking until the centre looks golden produces a hard, brittle flapjack. Check at 18 mins and remove as soon as the edges are deeply golden regardless of how the centre looks.
Leave to cool completely in the tin - at least 1 hour - before lifting out using the baking paper overhang. Cut into 16 squares or rectangles with a sharp knife using one clean downward press rather than a sawing motion. For the cleanest cuts, refrigerate for 20–30 mins before slicing.
If using a chocolate topping, spread the melted chocolate evenly over the completely cooled flapjacks and leave to set at room temperature or in the fridge for 20–30 mins before cutting.

Air Fryer Method

Preheat the air fryer to 150°C for 3–5 mins. Line a small square tin or silicone baking mould that fits your basket with baking paper - a 15–18cm tin works well for most standard air fryers.
Press the flapjack mixture firmly into the tin as directed. Place in the air fryer basket.
Cook for 14–16 mins until the edges are deeply golden and the centre still looks slightly underdone. Check at 12 mins - air fryers vary and flapjacks can catch quickly once the edges start to colour.

Tip: Use a lower temperature than you might expect - 150°C rather than 160°C - as the concentrated heat of the air fryer browns the edges faster than a conventional oven. The same rule applies: pull them out while the centre looks underdone. They firm up significantly as they cool.

Alternatives & Variations

Reduce the butter to 180g and replace the remaining 70g with the same weight of smooth peanut butter or almond butter - cuts saturated fat while adding protein and a nutty depth of flavour
Reduce the golden syrup to 100g and the brown sugar to 100g - less sweet but still holds together well; the oats provide natural sweetness
Add 50g of mixed seeds and reduce the oats by 50g - boosts the protein, fibre, and micronutrient content with minimal impact on texture
Use wholegrain rolled oats - they're the same as standard rolled oats but some brands specifically label them as wholegrain, providing a slight nutritional advantage

Swap the butter for vegan block butter - Naturli or Flora Plant both work well and produce an excellent flapjack. Golden syrup is already vegan. All other ingredients are plant-based. The result is virtually indistinguishable from the standard version.

Swap the rolled oats for certified gluten free rolled oats - oats are naturally gluten free but are frequently processed in facilities that handle wheat, so a dedicated gluten free oat is essential for those with a severe intolerance. Most major UK supermarkets stock certified gluten free oats (Tesco, Sainsbury's, and Waitrose all carry own-brand or Quaker gluten free versions). All other ingredients are naturally gluten free.

FAQs

Just 30 mins total - 10 mins of prep and 20 mins of baking. Factor in at least 1 hour of cooling time before cutting. One of the quickest baking recipes on the site with minimal equipment and washing up.

Rated Easy. There's no creaming, no whisking, no temperature-sensitive technique. The main things to get right are pressing the mixture down firmly before baking and pulling the flapjacks out of the oven while the centre still looks underdone. Both are straightforward once you know what to look for.

Almost always because they were overbaked. Flapjacks should come out of the oven looking underdone in the centre - the edges should be deeply golden but the centre should still look pale and slightly soft. They firm up considerably as they cool. If they're crumbly rather than chewy, the mixture may also not have been pressed down firmly enough before baking.

Yes - they freeze very well. Cool completely, cut into portions, and freeze in an airtight container or zip-lock bag for up to 3 months. Defrost at room temperature for 1–2 hours. They come back to an almost identical texture to fresh. A brilliant lunchbox freezer staple.

Stored in an airtight container at room temperature, flapjacks keep well for up to 7 days - one of the longer shelf lives of any baked good on the site. They actually improve on day two as the golden syrup continues to set and the chewiness develops. Don't refrigerate as it makes them hard.

Not recommended. Instant oats are pre-processed and much finer than rolled oats - they absorb more liquid and produce a denser, mushier flapjack that lacks the texture and chew of the rolled oat version. Rolled oats (also labelled as porridge oats at most UK supermarkets - check they're the whole rolled variety rather than quick cook) are the right choice here.

Yes - flapjacks work very well in the air fryer. Use a small tin that fits your basket, preheat to 150°C, and cook for 14–16 mins until the edges are deeply golden. Check from 12 mins and remove as soon as the edges are done regardless of how the centre looks - it will firm up as it cools. The result is very close to the oven version.