Preheat the oven to 350°F (175°C).

Butter two 9-inch cake pans and line the bottoms with parchment paper.

Butter the parchment paper.

In a bowl, whisk together the flour, baking powder, and salt.

In a separate large bowl, using an electric mixer, beat the granulated sugar with the almond paste until the paste turns into fine crumbs.

Add the softened butter to the almond paste mixture and beat until light and fluffy.

Add the eggs and egg yolks, one at a time, beating well after each addition.

Gradually stir in half of the dry ingredients into the wet ingredients.

Stir in the milk until just combined.

Add the remaining dry ingredients and mix until the batter is smooth.

Pour the batter evenly into the prepared cake pans.

Bake for about 40 minutes, or until a wooden skewer inserted into the center of each cake comes out clean.

Transfer the cakes to a wire rack and cool completely in their pans.

While the cakes are cooling, prepare the lemon frosting.

In a bowl, using an electric mixer, beat the softened butter with 1 1/2 cups of the sifted confectioners' sugar and the lemon zest until smooth and creamy.

Beat in the milk until the frosting is light and airy.

Stir in the remaining 2 cups of confectioners' sugar and beat until smooth.

Invert the cakes onto a clean work surface; peel off and discard the parchment paper.

Set one cake layer on a serving plate and spread the raspberry jam evenly over the top.

Carefully place the second cake layer on top of the jam.

Spread the lemon frosting evenly over the top and sides of the cake.

Sprinkle the toasted sliced almonds generously over the top of the cake.

Refrigerate the cake for at least 30 minutes to allow the frosting to firm up before serving.