Preheat oven to 350°F
In a large bowl with an electric mixer (a paddle attachment on a stand mixer works best for this recipe), beat peanut butter and butter until smooth.
1 cup smooth peanut butter, 1 cup unsalted butter room temperature
Add both white and brown sugar and beat on high speed until light and fluffy, about 2-3 minutes.
1 cup sugar, 1 cup brown sugar packed
Add eggs and vanilla and beat on low speed just until combined.
1 teaspoon vanilla extract, 2 eggs
Add flour, baking soda, and salt and beat on low speed just until the dough comes together.
3 cups all-purpose flour, 1 teaspoon baking soda, 1/2 teaspoon salt
Roll into 1" balls and place 2" apart on baking sheets. Press down slightly with a fork in a criss-cross pattern. (optional: roll the cookie balls in white sugar before pressing down with the fork)
Bake for 10-12 minutes, just until set
Remove and let cool on baking sheets.