Move the oven rack to the center of the oven. Preheat the oven to 350°F.
Prepare an 8x4 loaf pan by spraying the pan lightly with nonstick spray and then placing a piece of parchment paper into the pan.
Using a heavy-duty blender or food processor, pour in the milk, sugar, peanut butter, and eggs. Process for 1 to 2 minutes until a smooth batter, depending on the strength of your appliance.
Add in the flour, oats, baking powder, and salt then process until smooth which will take about 1 minute. If your appliance is lower wattage just add the dry ingredients gradually.
Pour batter into the prepared loaf pan.
Place in the oven and bake for 1 hour and 10 minutes or until a toothpick comes out clean or with just a few crumbs on it.
Remove from the oven and let rest in the pan for 10 minutes on a cooling rack before removing.
Allow the peanut butter bread to completely cool before slicing and serving. There are so many delicious optional toppings for this bread! You can top it with peanut butter, jelly, sliced bananas, etc.