Recipe
Monster Cookie Bars
Thick, chewy cookie bars packed with chocolate and marshmallows, topped with colourful sweets and playful edible eyes. A generous sharing treat with soft centres and plenty of sweet crunch.
Ingredients
Cookie bars
Decoration
Method
20 mins prep30 mins cook90 mins total
Prepare a 20cm square tin with parchment covering its base and sides, leaving handles to lift the bake. Set the oven to 180°C, 160°C fan or Gas 4.
Beat the butter with the brown and caster sugars for 2–3 minutes, then work in the egg and vanilla until evenly combined.
Combine the flour, baking powder, bicarbonate of soda and salt in another bowl. Fold this into the butter mixture just until the flour disappears.
Keep back a little chocolate for the top. Fold the rest, together with the mini marshmallows, through the thick dough.
Spread and press the dough into the tin, keeping exposed marshmallows to a minimum. Add the reserved chocolate across the surface.
Bake for 25–30 minutes. Look for set, golden edges and a middle that is still soft but not wet with raw dough; it will become firmer as it cools.
Leave the bake in its tin for 30–40 minutes. Add the colourful sweets when the surface is barely warm, and use the melted chocolate to secure the sugar eyes.
Lift out with the parchment and cut into twelve bars once the slab holds together cleanly. Cool fully before storing or stacking.
Notes
Keep most marshmallows inside the dough to reduce scorching, and add sugar eyes only after baking. Choose age-appropriate decorations; hard sweets are unsuitable for very young children.
Store airtight at room temperature for up to 3 days. Freeze undecorated bars for up to 2 months; thaw before adding the decorations.
About this recipe
These cookie bars have golden edges and a soft middle, with chocolate chunks running through a buttery brown-sugar dough. Mini marshmallows add little chewy pockets, while colourful sweets and sugar eyes make each square look different. Baking everything in one tin saves the extra work of shaping separate biscuits.
Use a small square tin to keep the bars thick, and tuck most of the marshmallows inside the dough rather than leaving them exposed. The slab firms as it cools, so give it time before lifting and slicing. Add the eyes after baking to keep their details sharp, then pack the finished bars in a single layer.
