Preheat the oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking pan.

Cream butter and sugar together in a bowl using an electric mixer. Add milk and egg yolks; mix dough to combine. Combine 2 1/2 cups flour, baking powder, and salt in a small bowl; add to dough and mix to combine. Press cookie layer into the prepared baking pan.

Spread raspberry jam over the base layer in the baking pan.

Beat eggs in a bowl until foamy. Add flour and keep beating until bright yellow. Mix in sugar and softened butter; beat until well combined. Stir in coconut. Spoon topping evenly over jam.

Bake in the preheated oven for 20 minutes. Turn the pan so bars bake evenly. Continue baking until topping is set, 15 to 20 minute more. Remove from oven and cool on a wire rack. Cut into bars.