Preheat your oven to 350 degrees F.

Prepare a 1 lb loaf pan (~ 9 x 5 x 3): either grease it, or line with parchment paper.

In a large bowl whisk the flour, baking powder and salt. Set aside.

Using an electric mixer cream together the butter and sugars.

Then add the peanut butter, egg and vanilla into the butter/sugar. Mix well.

Slowly add the dry ingredients, and combine. The mixture will be dry, but don't worry.

Pour in the milk slowly, and combine.

Pour the batter into a prepared loaf pan.

Bake for 50-60 minutes, or until a toothpick inserted into the centre comes out clean.

Let cool completely.