- Preheat oven to 190C.
- For the pastry, combine the flour, butter, coffee flour and sugar in a food processor and blitz until it resembles fine breadcrumbs. Add egg yolk and water and blitz to combine. Turn out of the food processor onto a bench and bring dough together. Wrap with plastic wrap and set aside in the fridge to rest for 30 minutes.
- Remove pastry from fridge. Cut into 4 pieces and roll each piece out. Line 4 x 10.5cm tart tins and prick the base of the tart with a fork. Place in freezer for 5 minutes. Cover with baking paper, fill with baking beans and blind bake pastry until golden brown, about 15 to 20 minutes. Set aside to cool.
- For the curd, whisk egg yolks and flour together. Combine zest, sugar and butter in a small saucepan and gently heat, dissolving the sugar. Pour the mixture into the egg yolk and flour, stirring continuously. Transfer mix to a small pan and return to a gentle heat, stirring continuously until the mixture thickens, about 2 minutes. Remove from heat and transfer to a bowl. Cover and set aside in the fridge to cool.
- For the ant praline, place ants on a lined baking tray. Place sugar in a pan and heat to a caramel colour. Once golden, pour over the ants and set aside in the fridge to set. Once set, break praline into small pieces and set aside.
- To make the filling, whip the cream with the sugar and transfer to a piping bag. Set aside.
- To assemble, remove pastry shell from the tart tin. Divide curd between tart shells. Place acha-cha on top of the curd and pipe sweetened cream over the top. Sprinkle with ant praline and garnish with extra sweetened cream.