Joan's Strawberry Thumbprints
3/4 cup butter at room temperature
1 cup sugar
1 egg yolk
2 teaspoons vanilla
1/2 teaspoon salt
1 cup ground walnuts
2 cups all-purpose flour
1/2 cup seedless strawberry jam
Beat butter, 1/2 of the sugar, yolk, vanilla and salt until fluffy. Ass walnuts and flour. Blend on low speed until combined. Dough will be crumbly but moist. Gather dough together with your hand to form a ball. Divide in half. Wrap in plastic wrap and refrigerate about an hour.
Heat oven to 375 degrees. Line two large baking sheets with non-stick foil or silpat. Bread off 1 tablespoon of dough and roll into ball. Then roll ball in remaining sugar to coat. Place on prepared sheets. Press a deep indentation in center, large enough to h old 1/2 teaspoon of jam. Repeat to form 36 cookies.
Bake at 375 for 12-14 minutes, rotating pans about halfway through, until lightly golden. Cool on pans on racks for 5 minutes. Use a spatula to transfer cookies to racks. Cool completely.