Set oven to 350F

Lightly spray a 9x9 square baking dish.

Beat the butter and sugar together until well blended.

Beat in the egg, vanilla, salt, and cinnamon. Fold in the apple butter and the chopped apples.

Fold in the flour, mixing just until combined.

Spread the batter evenly into the baking dish and bake for 30 minutes, or until set in the middle and a toothpick comes out without wet batter clinging to it (there can be moist crumbs.) Cool on a rack.

To make the maple frosting, put the maple syrup in a medium saucepan and bring it to a boil Boil for about 5 minutes, until reduced to 1/2 cup. Take off the heat and add the butter and cream and stir to combine and melt the butter. Whisk in the sifted powdered sugar and blend until smooth. Pour over the blondies and spread out with a spatula. The frosting will set up quickly so don't dawdle.