Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.
In a large mixing bowl, combine 1 cup creamy peanut butter and 1 cup granulated sugar. Mix until smooth and creamy.
Add 1 large egg and 1 teaspoon vanilla extract to the peanut butter mixture. Stir until fully incorporated.
Add 1/2 teaspoon baking soda and 1/4 teaspoon salt to the mixture and mix well.
Using a tablespoon, scoop out dough and roll into 1-inch balls. Place the balls on the prepared baking sheets about 2 inches apart.
Use the back of a fork to gently press down on each dough ball, creating a crisscross pattern and making an indentation in the center of each cookie.
Fill each indentation with about 1/2 teaspoon of strawberry jelly.
Bake the cookies in the preheated oven for 10 to 12 minutes, or until the edges are lightly golden.
Remove the cookies from the oven and allow them to cool on the baking sheets for 5 minutes before transferring to a wire rack to cool completely.