Massive macadamia and white chocolate gluten-free cookie

Preheat the oven to 170°C/150°C fan/gas mark 3-4 and line a large baking sheet with non-stick baking paper

Place the nuts on the lined baking sheet and roast for 5-10 minutes until light golden brown. Remove the nuts from the sheet and leave aside to cool a little

Melt the chocolate and butter together – the easiest way to do this is in a heatproof bowl in the microwave. Give it a 30 second blast, then stir gently. Three blasts in total should do it. Don’t worry if you overheat it slightly and the mixture curdles a little – it will still taste fine

Put the flour and sugar in a large mixing bowl and stir to combine

Whisk the egg with the vanilla paste and pour into the dry ingredients, then add the melted chocolate and butter and mix well

Transfer the mixture to the lined baking sheet and shape it into a circle about 30cm in diameter by pressing it out with your hands. The mixture will spread a bit in the oven so if you want a nice clean edge to your cookie you can contain it within a 30cm springform or loose-bottomed cake tin – use the tin ring minus its base on the baking sheet or simply bake the cookie in the cake tin

Arrange the macadamia nuts and chocolate chips on top and press them gently into the cookie dough

Bake for about 20–25 minutes until the surface feels fairly firm and dry to the touch. Leave to cool for a few minutes on the baking sheet, then run a knife around the circumference, carefully unmould and transfer to a wire rack to finish cooling and to firm up

When cool, decorate with more melted white chocolate if desired. You can mask off the centre of the cookie with a circle of foil, baking parchment, a large plate or the base of a loose bottom cake tin, then drizzle artistically around the edge. Add gluten-free sprinkles or popping candy if you wish

Cookie slices will keep in an airtight container for several days