In a microwavable bowl, put chocolate chunks and butter and microwave for 3 mins over med power, stirring every 30 secs. Allow to cool.
Fold into the bowl sugar and eggs, one at a time, whisking well until smooth. Add vanilla and cocoa, then fold in the flour and mix until just combined.
Pour the batter into a 9x9 baking pan covered with aluminium foil. Bake in a preheated oven to 350F/180C for 35 mins, you will see the brownies pulling away from the edges of the pan. Set aside to cool, then gently remove the top layer with a knife, and cut 6 small circles ( the same size of your ramekins). Set aside until needed.
For the Ricotta filling:
In a large bowl whisk energetically together the ricotta with sugar and zest of orange & lemon.
Cover 6 small muffin tins with plastic wrap and arrange a disk of brownie crust on each, gently pressing down to the bottom.
Evenly divide the ricotta filling into the tins, leaving 1cm space on top.
Put into the freezer while you make the mango puree.
For the mango puree:
Blend mango cubes with sugar and lime juice, adding 1 tablespoon water if the mixture is too thick.
Pour the mixture through a fine sieve into a bowl.
Cover each cheesecake with the mango puree and refrigerate until set, about 2h or overnight.
Gently remove from the muffin tin and decorate with fresh fruits and chocolate. Enjoy!