To make the bars: In a large saucepan, place the butter, brown sugar, and salt. Cook over medium heat, stirring regularly with a flexible spatula or wooden spoon, until the butter melts.

Preheat the oven to 350°F with a rack in the center.

Add the egg and almond extract, mixing until incorporated. Add the flours and salt and continue mixing until combined.

To add the topping: Top the frangipane with small spoonfuls of jam; 16 to 18 spoonfuls provides an even distribution, and a scant teaspoon cookie scoop works well here. Use the tip of a thin knife or toothpick to slightly swirl the jam with the frangipane. Sprinkle the sliced almonds over the top.

Remove from the oven and allow to cool completely, in the pan, on a wire rack.

When cool, remove the bars from the pan using the parchment overhang as handles. Garnish with a light sprinkling of non-melting or confectioners' sugar, then cut into slices before serving.

Store any leftover raspberry bars in an airtight container for several days at room temperature or store them in the refrigerator for a firmer texture.
Freeze the bars, well wrapped, for longer storage.