Preheat oven to 180 degrees C. Line a 20cm square baking dish with foil, and lightly grease the foil.
Place the flour, oats and sugar into a mixing bowl. Add the butter and mix, using your hands, until mixture has the consistency of coarse crumbs. Stir in the almond essence.
Remove 2 cups of the flour mixture and place in a separate bowl. Pour the remaining flour mixture into the prepared pan, and press evenly across the bottom. Spread raspberry jam over the flour layer. Gently press the reserved 2 cups of flour mixture over the jam. Sprinkle the top with almonds.
Bake in preheated oven until top is golden brown, about 30 minutes. Cool in the baking dish. Lift out foil to place square on a cutting board. Using sharp knife, cut into 9 squares.