Combine the confectioner’s sugar and almond flour in a bowl, then sift 3 times. Place the egg whites in a large bowl and beat with an electric mixer until foamy. Add the cream of tartar, then beat until soft peaks form. Add the superfine sugar and beat on high speed until stiff peaks form. Sift the dry mixture into the egg mixture and gently fold to combine. Divide the mixture into 3 bowls.
Separately puree and strain the mangoes and raspberries. Add 1 tsp mango puree and yellow food colouring to one bowl, 1 tsp raspberry puree and pink food colouring to another bowl and instant coffee powder to the remaining bowl. Gently fold to combine.
Place the batter in piping bags fitted with large round tips. Choose a round cookie cutter your desired size of ice cream sandwich. Pipe macarons in each colour (in even numbers) the same size as the cookie cutter onto baking sheets lined with parchment paper. Tap the baking sheets on your countertop a couple times to remove any air bubbles. Let the macarons sit at room temperature for 30 minutes.
Set your oven to 375F, heat for 5 minutes, then reduce the heat to 325F. Bake the macarons, one sheet at a time, for 15-20 minutes, rotating halfway through. The macarons should have the slightest hint of browning to them. These are quite big, so removing them from the oven when they are undercooked with cause them to deflate and you’ll have to start again from the beginning. After each batch, increase the heat to 375F, heat for 5 minutes, then reduce to 325F and pop the next sheet into the oven!
Allow the macarons to cool on the sheet until fully cool.