Preheat the oven to 180c/350f and line a deep 20cmx30cm baking tin with baking parchment. Leave a little of the parchment overhanging the tray to make it easier to get the brownie out later.
Melt the dark chocolate and butter together in the microwave in 30 second bursts, giving it a stir each 30 seconds (or you can melt in a bowl over a pan of simmering water - make sure the bowl isn't touching the water though). Stir and leave to cool slightly.
Whisk the eggs and sugar in a large bowl using an electric whisk until thick and creamy.
Slowly whisk again, and pour the melted chocolateand butter in. Pour it at the side of the bowl in a thin stream, whisking all the time, so that the eggs don't scramble with the warm chocolate.
When the chocolate is thoroughly mixed in, sieve the flour, cocoa powder and baking powder over the mixture, and then add the ground almonds. Fold into the mix gently, in a figure of eight. This will help to keep the air in.
Pour the mixture into your baking tray, and use a palette knife to ensure it goes all the way to the edges.
Place in the oven to cook for cook for 30 minutes.
Meanwhile make the cheesecake mixture. Add the cream to a large bowl and whisk with an electric whisk, until the cream holds its shape. Add the cream cheese, confectioners' sugar, vanilla extract and a pinch of salt, then whisk again until combined. Cover and refrigerate until needed.
When cooked, take the brownies out of the oven and leave to cool in the tray. When cool, lift the brownie out of the tray using the baking parchment and place on a chopping board.
Spread the cheesecake mixture on top, then dollop on the cherry pie filling.
Carefully cut the brownie in 20 pieces (5 by 4) using a sharp knife.
Serve immediately or cover and refrigerate for up to a day. Take out of the fridge an hour before serving to allow the brownie to soften slightly (as it firms up in the fridge).