Preheat the oven to 350 degrees.
Grease a 1/2 sheet pan or 9 by 13 cake pan.
Mix dry ingredients in a small bowl.
Whisk the coffee and butter together in a large bowl.
Add peanut butter and oil to the coffee and butter, whisk until smooth.
Add milk, vanilla, and eggs to the coffee mixture. Whisk well.
Incorporate the dry ingredients a little at a time. Mix well.
Pour into the prepared pan and bake for 30 minutes for a sheet cake and 40 minutes for a 9 by 13 pan. Check for doneness with a toothpick or knife entered into the center that comes out clean.
Frost with coffee buttercream and top with crushed salted peanuts.