First Step: Preheat the Oven and Prepare Your Tools Start by preheating your oven to 350 degrees F. This gives it time to reach the right temperature while you gather ingredients. Line a baking sheet with parchment paper to prevent sticking and make cleanup easy, adapting for any dietary swaps like vegan butter if needed.

Second Step: Cream the Butter and Sugars In a mixer with a paddle attachment, beat 4 ounces of room-temperature unsalted butter with ½ cup light brown sugar and ¼ cup white granulated sugar until light and fluffy. Scrape down the sides once to ensure everything mixes well. This step is crucial for the texture of your Eggnog Snickerdoodle Thumbprint Cookies, and using the right butter temperature helps avoid spreading.

Third Step: Add the Egg and Vanilla Next, add 1 medium room-temperature egg and 1 teaspoon vanilla extract to the mixture. Beat until creamy and fully combined, scraping down the sides again. For dietary adaptations, you could use a flax egg here if going vegan, keeping your Eggnog Snickerdoodle Thumbprint Cookies inclusive.

Fourth Step: Mix in the Dry Ingredients Sift together 245 grams all-purpose flour, ¼ teaspoon baking soda, ½ teaspoon cream of tartar, and ¼ teaspoon kosher salt. Add this to your wet mixture and stir until a thick dough forms. If you’re making gluten-free versions, swap the flour now to suit preferences, ensuring your Eggnog Snickerdoodle Thumbprint Cookies stay perfect.

Fifth Step: Shape the Cookies Scoop the dough into 1 tablespoon-sized balls, about 15 grams each. Roll them in the cinnamon-sugar mixture (⅓ cup sugar with 2 tablespoons cinnamon), then place on your prepared baking sheet. Press down the centers with a ½ teaspoon measure or your thumb; if it cracks, gently press it back. For low-calorie options, this is a good spot to adjust sizes.

Sixth Step: Bake the Cookies Bake for 7 minutes, then check if the indentation has filled in if so, gently press it down again while warm. Let them cool on the sheet for a few minutes before moving. This quick bake time makes Eggnog Snickerdoodle Thumbprint Cookies ideal for busy schedules, and you can adapt by chilling dough if needed.

Seventh Step: Make the Ganache Filling For the ganache, combine 4 ounces chopped white chocolate, 2 tablespoons eggnog, and 1 tablespoon dark rum or ¼ teaspoon rum extract in a bowl. Microwave in 15-second intervals, stirring between each, until melted about 45 seconds to 1 minute total. Alternatively, use a double boiler, then stir in ¼ teaspoon freshly grated nutmeg. This step adds that signature flavor, and for kid-friendly versions, skip the rum.

Final Step: Fill and Set the Cookies Fill each cookie’s center with about ½ teaspoon of ganache and top with a bit more grated nutmeg. Let them set at room temperature for a few hours or chill in the fridge to speed it up. Serve these Eggnog Snickerdoodle Thumbprint Cookies warm for the best taste, and feel free to experiment with variations for different tastes.