Pastry: Sift flour and icing sugar into a bowl and rub in fats. Stir in milk and bring together into a soft dough. DO NOT over work to avoid pastry being rubbery. Chill for 30 mins and preheat oven 200c or 180c for fan
Line a 10"x10" baking tin. Roll out pastry into a square and roll over rolling pin. Lay into baking tin and gently press into corners with your knuckle. If pastry doesn't reach the top or there are tears use milk to patch up. Blind bake for around 10 mins, when your cake batter is ready and jam is softened the pastry should be ready
Sponge: Cream butter and sugar very well until light and fluffy. At max speed beat in eggs one at a time. Room temp eggs avoid splitting and help achieve an even bake.
Once eggs are well mixed in beat in flavourings and milk and beat a little until fluffier. Sift in flour and baking powder and mix on slowest speed until just combined. Again do not over work. Soften 3 quarters of a standard jar of jam in a bowl
Remove pastry from the oven and spread on the jam. Pour on the cake mix, starting with the edges so jam doesn't spread too much. Even the top and bake 35-45 mins