Preheat oven to 375F and line a 8x8” baking pan with parchment paper.
Shortbread: In a stand mixer, beat butter until smooth and creamy. Add in sugar and cream together until smooth. Add in egg and vanilla and beat again. Add in dry ingredients and stir until completely combined. Press the shortbread mix firmly into the bottom of the baking pan, making it as even as possible. Bake for 10 minutes while making the frangipane.
Frangipane: In a stand mixer, beat butter, sugar and salt together until smooth. Add in the remaining ingredients and stir until fully mixed.
Remove shortbread from oven and top with frangipane, spreading evenly. Sprinkle the top with sliced almonds.
Bake for 20-22 minutes.
Allow to cool completely before dusting with powdered sugar (if desired) and slicing. Enjoy!