Prepare the cherry filling by combining cherries, sugar, water, and lemon juice in a saucepan. Heat until boiling, then add cornstarch slurry and cook until thickened.

Preheat the oven to 350°F and line a baking sheet with parchment paper.

Sift together almond flour, tapioca flour, and kosher salt in a medium bowl. Set aside.

Cream butter and sugar in a mixer until light and fluffy. Mix in vanilla and almond extract.

Gradually incorporate the dry ingredients into the wet mixture until a soft dough forms.

Roll dough into 1-inch balls, coat in granulated sugar, and press deep thumbprints into each ball.

Fill each thumbprint with cooled cherry filling. Bake for 14-15 minutes until lightly golden.

Cool on baking sheet for 5 minutes, then transfer to a wire rack to cool completely.