Preheat oven to 350°.
Place brown sugar and butter in a large bowl; beat with a mixer at medium speed until well blended (about 3 minutes). Add persimmon puree, molasses, and eggs; beat well (about 1 minute).
Lightly spoon flour into dry measuring cups; level with a knife. Sift together flour and next 6 ingredients (through cloves). Add flour mixture and 1/3 cup boiling water alternately to persimmon mixture, beginning and ending with flour mixture. Stir in almonds. Pour batter into a 9-inch square baking pan coated with cooking spray. Bake at 350° for 30 minutes. Cool 10 minutes in pan on a wire rack. Dust with powdered sugar. Cut into 12 squares.
Persimmon Puree Pointers. Ripe Hachiya puree is easy to make by following these tips:
To speed the ripening process, freeze the fruit overnight or until solid. Thaw the persimmon; when soft, it will be sweeter and less astringent.
Cut the ripe fruit in half. Scoop the pulp out with a spoon.
To achieve an even consistency, place the flesh in a mini-chopper and process until smooth. This ensures the persimmon puree will incorporate evenly into the batter.