I saw this recipe on Facebook last week. It is from a website called Mr. Food. This cake is so delicious...very peanutty. I would suggest a slightly shorter baking time so I am reducing the time by 5 minutes in the directions. You can probably tell the edges of mine were a little too dark. This recipe makes 2 cakes but is easy to divide in half if you just want one.
Preheat oven to 350°. Coat 2 loaf pans (9x5) with Pam.
Combine butter and sugar in large mixer bowl and beat until fluffy. Add the eggs, one at a time, beating after each one. Mix in the peanut butter and flour.
Divide the batter evenly between the 2 pans. Bake for 20 minutes. Remove loaves and sprinkle with chopped peanuts. Return to the oven for an additional 25-30 minutes. Remove loaves to a cooling rack and let cool completely before slicing.