To prepare cake, coat 2 (8-inch) round metal cake pans with cooking spray. Line bottoms of pans with wax paper; coat with cooking spray. Dust each pan with 1 teaspoon flour. Weigh or lightly spoon 9 ounces flour (about 2 cups) into dry measuring cups; level with a knife.
Combine 9 ounces flour, baking soda, and next 4 ingredients (through cloves), stirring well with a whisk.
Place 1 cup brown sugar and 1/2 cup butter in a large mixing bowl; beat with a mixer at medium-high speed until light and fluffy (about 3 minutes).
Add eggs, 1 at a time, beating well after each addition. Beat in 1 teaspoon vanilla.
Add flour mixture and buttermilk alternately to butter mixture, beginning and ending with flour mixture and beating just until combined. Fold in 1/3 cup pecans. Divide batter evenly between prepared pans.
Bake at 350 for 24 minutes or until a wooden pick inserted in center comes out clean. Cool in pans 5 minutes on wire racks. Invert cake layers onto racks; cool completely. Discard wax paper.
To prepare frosting, place 1/2 cup brown sugar, heavy whipping cream, maple syrup, 1 tablespoon butter, and dash of salt in a heavy saucepan over medium-high heat; bring to a boil, stirring just until sugar dissolves. Cook 3 minutes, without stirring. Scrape brown sugar mixture into a bowl.
Add powdered sugar; beat with a mixer at high speed 2 minutes or until slightly cooled and thick. Beat in 1/2 teaspoon vanilla.
Place 1 cake layer on a plate.
Spread about 3/4 cup frosting evenly over 1 layer; top with second layer.
Spread remaining frosting over sides and top of cake; sprinkle with 2 tablespoons pecans.
