Heat oven to 350° F (177° C). Line a small baking sheet with parchment paper or a silicone baking mat.
Using an electric hand mixer, cream the butter and sugar together until light and fluffy. This process should take about 1 minute for the best texture.
Add the egg yolk and vanilla to the mixture, blending well to ensure a uniform consistency.
Gently mix in the flour, ensuring it’s fully incorporated into the batter.
Scoop the dough into 1 ½ tablespoon-sized portions and place them on a cookie sheet. Roll each portion into a smooth ball.
Press a hole into the center of each ball, using your thumb or a 1 teaspoon measuring spoon for uniformity.
Spoon about 1/2 teaspoon of jam into each thumbprint.
Place the cookies in the oven and bake for 8 to 10 minutes, until they’re perfectly set and lightly golden.Pro Tip: Consider sprinkling powdered sugar over the baked thumbprint cookies. This adds a delightful touch, particularly when presenting these cookies as part of a holiday food gift.
Notes
Before starting, it’s important to read the entire recipe and the detailed Ingredient Notes section. We’ve included comprehensive information to guarantee your thumbprint cookies turn out perfectly every time. Since these cookies are quick to make, it’s essential to familiarize yourself with the recipe and have all ingredients prepped and ready to go before beginning.
Optional Sugar Coating: While I typically don’t do this, you have the option to roll the balls of cookie dough in granulated sugar for added sweetness and texture. This step is entirely up to your preference.
Accurate Measuring: For the best results, spoon your flour into a dry measuring cup rather than scooping it directly. Overfill the cup slightly, then level it off with a straight-edged utensil like the back of a knife. Scooping packs the flour too tightly, leading to an inaccurate measurement that can affect your cookie’s texture.
Jam Consistency: Room temperature jam is easier to spoon and won’t stiffen the dough.