Preheat oven to 350°.Butter a 9 by 13 inch pan and set aside.

Cream peanut butter,cream cheese and sugar until creamy then stir in the egg and milk.Set aside

For the filling,cream melted butter,sugar and vanilla.Beat in the eggs one at a time then mix in rest of ingredients.Mix well!

Reserve 1 cup of batter for top and spread the rest in the pan.Spoon filling on top by tablespoonfuls then carefully spread it evenly on.

Drop the remaining batter on top by spoonfuls and spread the best you can.Take a kitchen knife and swirl through everything until it is nicely marbled.Bake for 40-50 minutes or until a wooden toothpick comes out almost clean.

*Variation* For a mocha twist,mix 2 teaspoons instant coffee with the butter while it is melting so that it will dissolve.Then mix batter as directed in step 3.