Heat the oven to 175 C / 350 F. Line an 8x8-inch baking pan with parchment paper, leaving an overhang on two sides for easy lifting.

Combine all-purpose flour, almond flour, powdered sugar, and salt in a mixing bowl. Add cold cubed butter and rub in with your fingertips or a pastry cutter until the mixture resembles coarse, damp sand.

Press the shortbread mixture firmly and evenly into the lined pan using the back of a spoon or your fingers. The layer should be about 6 mm thick with no thin patches.

Bake for 12 to 14 minutes until the edges are just starting to turn golden. Remove and let cool in the pan for 5 minutes.

Spoon the raspberry jam over the warm base. Spread in an even layer with an offset spatula, leaving a 5 mm border around the edges.

Whisk together almond flour, powdered sugar, melted butter, eggs, and almond extract in a bowl until smooth and slightly glossy.

Pour the almond topping evenly over the jam layer and smooth it gently with a spatula. Scatter sliced almonds over the surface.

Bake for 20 to 22 minutes until the topping is set, golden at the edges, and a toothpick inserted in the center comes out with only a few moist crumbs.

Let the bars cool completely in the pan, at least 30 minutes, before lifting out using the parchment overhang.

Transfer to a cutting board and slice into 16 bars with a sharp knife. Wipe the blade clean between cuts for neat edges.