These thumbprint cookies are truly the best! They're buttery shortbread cookies, rolled in crushed walnuts and filled with jam! Truly one of our favorite cookie recipes ever using only 6 simple ingredients.
Preheat and prep – Preheat the oven to 375°F and line a baking sheet with parchment. Separate the egg yolks and whites, and quickly whisk the flour to remove lumps. Measure the brown sugar by packing the measuring cup.
Mix – Cream the butter and brown sugar together. Add in the egg yolks and flour and mix on medium until fully combined.
Crush the walnuts – In a food processor or blender, pulse the walnuts until finely chopped. Pour them into a shallow plate or bowl.
Roll the dough – Use a melon baller to scoop the dough and hand roll it into smooth balls. Smooth balls prevent cracking when you press the centers.
Coat the cookies – Roll the balls in egg whites and then the chopped walnuts to cover the entire ball.
Prepare for baking – Place 12 cookies on the lined baking sheet and press down in the middle using a small round measuring teaspoon to make a "thumbprint."
Bake first time – Bake for 10 to 12 minutes. You will bake again after they are filled.
Fill the cookies with jam – Spoon about ½ teaspoon of jam into each thumbprint, just until filled.
Then bake again – Place them back in the oven and bake again for 5 minutes.
Bake again – Return to the oven for 5 more minutes. Cool completely on a wire rack so the jam sets.
Notes
Use any jam you prefer to fill these thumbprint cookies.Correctly measure the flour. Always use whole, organic ingredients when possible. Remember, these are baked twice in the oven, so don't forget to place them back in for 5 minutes after filling them with jam. Salted or unsalted butter works for this recipe. Use a small round kitchen tool like a teaspoon to make the "thumbprints" a perfect circle.Storage + Freezing
Room temperature: 3 days in an airtight container
Refrigerator: Up to 1 week
Freezer: Freeze baked cookies or unbaked dough balls up to 3 months