Preheat oven to 375 degrees F. Line two cookie sheets with parchment paper or silicone baking mats and set aside.
In the bowl of a standing mixer, or in a large bowl with a hand-held mixer, cream butter and sugar until light and fluffy. You may need to pause, scrape down the sides and continue beating.
Add vanilla & beat until combined.
Add sifted flour and sea salt and beat on medium-high speed until the dough forms large “crumbs” and pinches together easily.
Measure out 1 TBS portions of dough and roll into balls.
Place the dough balls on the prepared cookie sheet and press your thumb into the center of each dough ball to form a well and slightly flatten the cookies.
Fill each well of the cookies with about 1 tsp of jam – don’t let it overflow the well.
Bake for 10 to 13 minutes or until the cookies just being to turn golden brown at the edges.
Let them cool on the pan for 10 minutes before removing to a wire rack to cool completely (or enjoy slightly warm – they are so good).
Salted butter. Unsalted butter works well, just increase the sea salt from ¼ to ½ teaspoon.
Granulated sugar. organic cane sugar can be used in place of regular white sugar.
Pure vanilla extract. the rich flavor imparted by the vanilla extract is essential to making the best thumbprint cookies, you can use almond extract or use half vanilla half almond extracts for a yummy combination.
All-purpose flour. I don't recommend making substitutions, as I have not tried using a different flour.
Jam. We prefer to make raspberry thumbprint cookies because it's our favorite jam and the color is festive for the holidays. You can use any flavor you prefer such as apricot, strawberry, cherry, etc.
To store, let the thumbprint cookies cool completely. Then, store them in a single layer or in layers with waxed paper in between, in an airtight container at room temperature for up to 3 days, in the refrigerator for up to 1 week or in the freezer for up to 2 months.
How to freeze thumbprint cookie dough
Portion out the dough and roll it into balls and press in the wells. Then place prepared dough on a baking sheet and flash-freeze them until hardened. Once hardened, transfer the dough balls to an airtight container and freeze until you're ready to bake.
To bake: remove the dough from the freezer and let it thaw in the refrigerator overnight or at room temperature for 2 hours. Once thawed, fill with jam and then baked according to the recipe instructions.