Classic Thumbprint Cookies with a sweet jam center are the perfect cookie to enjoy any time of the year! These cookies are buttery, fruity, and drizzled with just the right amount of sweet glaze.
Preheat oven to 350 degrees. Line 2 baking sheets with parchment and set aside.
Cream butter and sugar together with a hand or stand mixer until fluffy. Add egg yolk and mix well.
Slowly add flour, 1/2 cup at a time, and continue to mix - the dough will be thick and dense.
Using a spoon or a #40 scoop, form cookie dough into small balls. Place on prepared cookie sheets.
Using your thumb, or the bottom of a wooden spoon make an indention in the center of the cookie and fill it with preserves.
Bake for 18 minutes. Remove from oven and let cookies rest on the pan for 1 minute.
Remove from baking sheet and let cool on a wire rack.
Mix together confectioners sugar and lemon juice (milk or water.) Stir until smooth. Drizzle over cookies.
Enjoy!