Preheat oven to 350°F (175°C). Line two baking sheets with parchment paper or silicone baking mats.

In a large bowl, cream together 1 cup (2 sticks) unsalted butter and 1/2 cup granulated sugar for 2–3 minutes until light and fluffy.

Add 1 teaspoon vanilla extract. In a separate bowl, whisk together 2 cups all-purpose flour, 1/2 cup unsweetened cocoa powder, and 1/4 teaspoon salt. Gradually mix dry ingredients into the butter mixture until just combined.

Roll dough into 1-inch balls and place 2 inches apart on prepared baking sheets. Use your thumb to press an indentation into each ball.

Fill each indentation with about 1/2 teaspoon seedless raspberry jam.

Bake for 12–14 minutes, until the edges are set and centers remain glossy. Let rest on the baking sheet for 5 minutes before transferring to a wire rack.