Preheat oven to 350 degrees F. Grease and flour to round cake pans.
In a large bowl cream the brown sugar, granulated sugar, and butter with an electric mixer.
Add the eggs and mix in.
Sift together the flour, baking soda, salt, and cinnamon, gradually add to the creamed mixture alternating with the buttermilk.
Fold in the apples and peanuts.
Divide batter between the two cake pans. Place in a preheat oven and bake for 30 to 35 minutes or until a wooden pick inserted comes out clean.
Remove from oven and cool on cooling racks. Remove from cake pans and cool completely.
Add brown sugar, cream and 2 tablespoons butter to a saucepan. Bring to a boil over medium heat. Stirring constantly cook for a minute or two, so that it thickens slightly. Remove from heat and cool completely.
Add the remaining 6 tablespoons of butter and cream cheese in a medium bowl. Beat with an electric mixer until just mix together.
Add the cooled caramel mixture and vanilla, mix just until mix in.
Add enough of the powdered sugar to make the frosting the right consistency
Place one of the layers of cake on cake platter. spread the top with frosting.
Place the other layer of cake on top. Spread with the rest of the frosting
Sprinkle with addition chopped peanuts if desired.