Preheat oven to 325°F / 165°C. Line a 9×9 pan with parchment.
Cream butter and sugar just until smooth.
Mix in vanilla and almond extract.
Whisk flour, cornstarch, and salt. Add to the bowl and mix just until a dough forms.
Press evenly into pan, smooth the top.
Bake 35–40 minutes, until pale with lightly golden edges. Then sprinkle with sugar while still warm.
Cool completely, then cut into rectangles and enjoy!
