Heat the oven to 350°F (175°C). Grease an 8-inch square baking pan and line it with parchment, leaving enough overhang to lift the cooled bars out easily.

Cream the softened butter and granulated sugar until light and smooth. Beat in the egg, vanilla extract, and almond extract until fully combined.

In a separate bowl, whisk together the flour, baking powder, and salt. Add the dry mixture to the butter mixture and mix just until a soft dough forms.

Press about two-thirds of the dough evenly into the prepared pan. Spread the raspberry preserves over the crust, leaving a narrow border around the edge.

Crumble the remaining dough over the jam and scatter the sliced almonds evenly over the top. If the dough is too soft to crumble, chill or freeze it briefly first.

Bake for 25–30 minutes, or until the top is lightly golden and the raspberry filling is bubbling at the edges. Cool the bars completely in the pan before cutting.

For the optional glaze, whisk the confectioners’ sugar, milk or cream, and almond extract until smooth. Drizzle it over the completely cooled bars, then allow it to set before serving.