Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large mixing bowl, combine the peanut butter and brown sugar. Stir until smooth and creamy.

Add the egg and vanilla extract to the bowl, mixing until fully incorporated.

Sprinkle in the baking soda and salt, and mix until the dough comes together and is evenly blended.

Scoop out about 1 tablespoon of dough for each cookie and roll it into a ball. Place the dough balls onto the prepared baking sheet, spacing them about 2 inches apart.

Use a fork to gently press down on each dough ball, creating a criss-cross pattern on the top of each cookie.

Bake in the preheated oven for 10-12 minutes, or until the cookies are golden around the edges.

Remove from the oven and let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.