Preheat the oven to 300°F and place ungreased baking sheets nearby.
In a large mixing bowl, add flour, baking soda, salt, dark brown sugar, and white sugar.
Mix the dry ingredients together and set the bowl aside.
In a second large mixing bowl, add the dark brown sugar and white sugar.
Using an electric mixer on medium speed, blend the sugars until combined.
Add the softened butter to the sugar mixture and mix until the texture becomes grainy.
Add the eggs, peanut butter, and vanilla extract to the bowl.
Beat the mixture with the electric mixer until it becomes light and fluffy.
Turn the electric mixer to low speed.
Slowly add the flour mixture to the butter mixture and mix until just combined.
Using a tablespoon, scoop rounded portions of dough.
Place the dough portions 2 inches apart on the ungreased baking sheets.
Wet a fork with water or coat it with flour.
Gently press the fork onto each cookie to create a crisscross pattern on top.
Place the baking sheets in the oven and bake for 18 to 20 minutes, until the edges turn light brown.
Remove the baking sheets from the oven and transfer the cookies to a cooling rack.
Allow the cookies to cool completely on a flat surface.
Store the cooled cookies in an airtight container.
Notes
Tips and Tricks
Don't Overmix the Dough - Mix the flour mixture into the butter mixture just until combined. Overmixing can make the cookies tough instead of soft.Use Room Temperature Butter - Softened butter blends more easily with the sugar and creates a better texture. Leave the butter out for about 30 minutes before starting.Space the Cookies Properly - Place the dough portions 2 inches apart on the baking sheets. The cookies will spread slightly as they bake.Press Gently with the Fork - When creating the crisscross pattern, press lightly. Pressing too hard can flatten the cookies too much.Watch the Baking Time - Check the cookies at 18 minutes. The edges should be lightly browned, but the centers may still look slightly soft. They will firm up as they cool.Cool on the Baking Sheet First - Let the cookies sit on the baking sheet for 2 to 3 minutes before transferring them to a cooling rack. This prevents them from breaking.
Storing
Room Temperature - Store the cookies in an airtight container at room temperature for up to 5 days. Place parchment paper between layers to prevent sticking.Refrigerator - The cookies can be refrigerated in an airtight container for up to 2 weeks. Bring them to room temperature before serving for the best texture.Freezer - Freeze the cookies in a freezer-safe container or bag for up to 3 months. Separate layers with parchment paper. Thaw at room temperature for 15 to 20 minutes before serving.