1-First Step: Preheat and Prep: Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper to prevent sticking and promote even browning. This setup takes 5 minutes and avoids greasy cookies. Gather all ingredients for smooth workflow. Measure peanut butter and sugar first, as they form the dough base.

2-Second Step: Mix the Dough: In a large bowl, combine 1 cup creamy peanut butter, 1 cup sugar, 1 large egg, and 1 teaspoon vanilla extract. Stir with a wooden spoon or spatula until smooth and fully blended, about 2 minutes. The mixture thickens quickly due to the egg. Avoid overmixing to keep texture light. If dough feels sticky, chill for 10 minutes.

3-Third Step: Shape the Cookies: Scoop dough into 1-inch balls using a cookie scoop or tablespoon. This yields about 24 peanut butter thumbprint cookies with Nutella. Roll each between palms for even rounds. Place balls 2 inches apart on the prepared sheet. Space prevents spreading into each other during bake.

4-Fourth Step: Create the Thumbprints: Gently press your thumb (or end of a wooden spoon) into the center of each ball, creating a 1/2-inch deep indent. Rotate slightly for round shape. Do not press to the bottom, or filling leaks. Re-press indents halfway through baking if they puff up. This step defines classic thumbprint cookies.

5-Final Step: Fill and Cool: Remove from oven and cool on sheet for 5 minutes. This sets structure and prevents breakage. Spoon or pipe 1 teaspoon Nutella into each indent. Nutella softens from residual heat, settling perfectly. Transfer to wire rack to cool fully, about 20 minutes. Enjoy warm or room temp.