Preheat oven to 350F. Line two baking sheets with parchment paper.

In a medium bowl, whisk together flour, baking soda, and salt. Set aside.

In a large bowl with an electric mixer, beat softened butter and peanut butter on medium speed until smooth and combined, about 1 minute. Add both sugars and beat until light and fluffy, 2 to 3 minutes, scraping down the bowl as needed.

Beat in the egg and vanilla until fully incorporated, about 30 seconds.

With mixer on low, gradually add the flour mixture and mix just until no dry streaks remain. Do not overmix.

Scoop 1-inch balls of dough and roll in granulated sugar to coat lightly. Place 2 inches apart on prepared sheets. Use your thumb or the back of a 1/2 teaspoon measure to press a deep well into the center of each cookie. Fill each well with 1/2 teaspoon of jelly.

Bake until edges are set and tops look slightly cracked, 10 to 12 minutes. The centers will still look soft. Let cool on pans for 5 minutes, then transfer to wire racks to cool completely.