Preheat the oven to 375ºF. Line 15 muffin cups with liners, or spray with nonstick cooking spray.
In a large bowl, beat together the peanut butter, oil, and sugar. I like to do this for a couple of minutes.
1 cup peanut butter, 1/2 cup neutral cooking oil, 1 cup light brown sugar
Add in the eggs and beat until combined. Mix in the milk and the vanilla.
2 eggs, 1 cup milk, 1 teaspoon vanilla extract
Add the flour, baking powder, and salt. Mix just until all of the ingredients are combined.
2 cups all purpose flour, 1 tablespoon baking powder, 1/2 teaspoon salt
Divide the batter evenly between the prepared muffin cups. They should be almost full.
Bake until a tester inserted in the center comes out almost clean, with just a few crumbs, about 20-23 minutes.
Let cool slightly before serving.
Notes
Nutrition information provided as an estimate only. Various brands and products can change the counts. Any nutritional information should be used as a general guide.