"Great cake for birthdays or other celebrations. The combination of the peanut butter filling and this frosting makes this a very rich cake. This is not a "fluffy" frosting so if that's what you like you might want to try a different recipe for the frosting."
In a large mixing bowl, sift together dry ingredients. Add oil, coffee and milk and mix at medium speed for 2 minutes. Add eggs and vanilla and beat 2 more minutes. Expect batter to be thin.
Pour into a 9" x 13" greased and floured pan or 2- 9" round pans. Bake 9 x 13 pan for about 45 minutes or 9" pans for about 30 minutes. Cool in pans for about 15 minutes and then cool completely on rack.
In a large bowl, beat butter and peanut butter until light and fluffy. Slowly beat in 1/2 of the confectioner's sugar. Mix in 1/4 cup of the cream. Beat in the remaining confectioners' sugar. If necessary, add a little more cream or milk for a good spreading consistency. Spread between layers of cake.
In a bowl, beat together the cream cheese,milk, confectioner's sugar, butter, vanilla, cocoa, and cinnamon to a spreadable consistency. Beat in additional milk if necessary. For a darker frosting add more cocoa or up to 4 ounces melted chocolate. Spread onto cooled cake.