Heat the oven to 350°F and line two baking sheets with parchment paper.
Whisk the all-purpose flour, almond flour and salt together in a medium bowl.
Beat the softened butter and granulated sugar with a hand mixer until light and fluffy, about 2 minutes. Beat in the egg yolk and vanilla until smooth.
Add the dry ingredients in two additions and mix on low just until a soft dough forms; stop as soon as no dry streaks remain.
Roll the dough into 1-tablespoon balls and set them 2 inches apart on the sheets. Press a deep well into each with your thumb or the back of a 1/2-teaspoon measure, pressing almost to the bottom.
Spoon about 1/2 teaspoon of raspberry jam into each well; do not overfill or it will bubble over.
Bake one sheet at a time for 12 to 14 minutes, until the edges are set and barely golden. Cool on the sheet for 5 minutes, then transfer to a wire rack.
Dust with powdered sugar once the cookies are completely cool, if using.
