Melt the butter and set aside to cool slightly. Place the biscuits in a food processor and process until the mixture resembles fine crumbs. Add the butter and the cinnamon and whizz to combine. Line 6 muffin pans with paper muffin cases and press the biscuit mixture into the base of each. Refrigerate for 15 min to set.
Meanwhile, place the ricotta, cream cheese, lemon zest and juice, icing sugar, egg and yolk, and cream in the bowl of an electric mixer (or use an electric hand beater), and beat until smooth. Fill each paper muffin case to within 1cm of the edge, then top with 3 or 4 berries. Bake for 25 minutes, then turn off the oven and leave them to cool with the door closed (this prevents them from cracking).