Whisk together the flour, baking powder, sugar and salt.
Add the milk and peanut butter. Beat with a hand mixer or mix by hand until thoroughly combined. Do not overmix.
Pour the batter into a 9 inch loaf pan coated with cooking spray and transfer to the oven.
Bake the bread for 1 hour or until a toothpick inserted into the center comes out clean.
Allow the bread to cool for 10 minutes and then remove from the pan to a cooling rack. Cool to room temperature.
Notes
Peanut Butter bread can be stored at room temperature for up to 5 days in an airtight container.You can also freeze your peanut butter bread for up to 3 months wrapped tightly in plastic wrap and then a layer of foil.