1-Melt the 200g dark chocolate and 150g unsalted butter together gently in a heatproof bowl over simmering water or in short bursts in the microwave. Stir until smooth for that perfect base.

2-In a separate bowl, beat the 3 large eggs and 200g caster sugar until pale and fluffy, then gradually add the melted chocolate mixture and mix well.

3-Sift the 100g plain flour and 1 tsp mixed spice into the wet ingredients, folding gently to keep it airy, then stir in the 50g chopped nuts and 1 tsp vanilla extract.

4-Pour the double batch of batter evenly into the prepared metal pan, smoothing the top with a spatula for even results.

5-Bake for about 35 minutes, or until a skewer comes out with moist crumbs. Let it cool completely, then chill for at least two hours or overnight to firm up for easier cutting.

Once chilled, remove the brownies from the pan using the parchment or foil. For the fun part, use cookie cutters to stamp out shapes, placing them close together and lifting carefully chilling makes this step cleaner and easier. Prepare the buttercream frosting separately, divide it into bowls, and color as desired. Frost each shape while still wet to help sprinkles, mini chocolate chips, or mini candies stick well. Frosting can be spread with a knife or piped based on your skill level!