See Recipe Tip for details of how to make a ... the bowl of a freestanding mixer fitted with a whisk), beat the butter and peanut butter together very thoroughly; that’s to say, for 3 minutes ...
Line a round 9 inch spring form tin with parchment and preheat your oven to 170 degrees. Melt the butter in a heavy base saucepan large enough to accommodate all of the crushed biscuits.