1-First Step: Prepare the Mise en Place Soften 1 cup butter at room temperature for 30 minutes. Measure 1/2 cup sugar, 2 egg yolks, 1 tsp vanilla, 2 cups flour, and 1/2 tsp salt into bowls. Line two baking sheets with parchment paper. This setup keeps things organized, preventing last-minute scrambles. For best results, use unsalted butter to control saltiness. Have 1/3 cup jam ready in a small bowl; stir if thick.

2-Second Step: Cream Butter and Sugar In a large bowl, beat softened butter and sugar with an electric mixer on medium speed for 2-3 minutes until light and fluffy. Scrape sides often for even mixing. This step incorporates air, yielding tender cookies. Add 2 egg yolks and 1 tsp vanilla; beat 1 more minute. The mixture should look pale and creamy. If hand-mixing, use a sturdy spoon and extra elbow grease.

3-Third Step: Incorporate Dry Ingredients Sift 2 cups flour and 1/2 tsp salt together. Gradually add to wet mixture on low speed, mixing just until a soft dough forms. Avoid overmixing to prevent tough cookies. Dough will be slightly sticky; that’s normal. If too sticky, chill 10 minutes. Wrap in plastic and refrigerate 30 minutes. Chilling firms the butter, helping cookies hold shape.

4-Fourth Step: Shape the Cookies Preheat oven to 350°F. Scoop 1-inch dough balls using a tablespoon or melon baller. Roll smoothly between palms for even spheres. Place 2 inches apart on prepared sheets. Gently press thumb into each center, rotating for a neat indent about 1/2-inch deep. Don’t press too hard or edges crack excessively. Optional: roll balls in chopped nuts before indenting for added texture.

5-Fifth Step: First Bake Bake 8 minutes until edges set but centers remain soft. Remove from oven; immediately re-press indents with thumb end of a wooden spoon dipped in sugar to prevent sticking. This preserves space for filling. Edges may puff; pressing firms them. Return to oven for 7-10 minutes until lightly golden. Watch closely to avoid overbaking, which dries them out.

6-Sixth Step: Cool and Fill Cool cookies on sheets 5 minutes, then transfer to wire racks. Once fully cool (about 20 minutes), spoon 1/2 tsp jam or melted chocolate into each indent. Use a piping bag for neatness. For chocolate, melt 1/3 cup chips with 1 tsp butter. Let set 10 minutes. Filled cookies taste best fresh but store well. Yield: 30 cookies. Total time: 30 minutes active, plus chilling.