Heat oven to 220C/fan 200C/gas 7. Stir the custard and almonds together. Unroll the pastry, then cut out circles using a 7cm plain round cutter. Gather up the pastry trimmings, re-roll, then cut out more circles – you should get 16-18. Use to line a couple of bun tins.
Spoon a heaped tsp of the custard mix into each tart case, then top with a scant tsp of mincemeat. Scatter over some flaked almonds, then bake for about 10 mins until puffy and golden. Cool briefly in the tin, then dust with icing sugar and serve slightly warm.