Adjust oven rack to one third up from the bottom. Preheat the oven to 350°. Spray three loaf pans (8 1/4 x 4 1/2 x 2") with nonstick vegetable spray. Cut out two pieces of parchment paper to line the bottom of each pan and press into the pan. Spray the parchment with vegetable spray and set aside.
In a medium bowl, sift the flour, baking powder, baking soda and salt. Set aside.
In a large mixing bowl or using a stand mixer, add the butter and beat on medium speed until light and fluffy. Add the mace and vanilla and mix in. Add the brown sugar a cup at a time until it's completely incorporated into the butter. Add eggs one at a time, beating until completely blended after each addition. Add the bananas and mix until well combined.
In a 1 cup glass measuring cup measure out 3/4 cup milk and add 1/4 cup bourbon to equal one cup.
On the lowest speed, alternate adding the dry ingredients with the wet ingredients in 3 additions, ending with the wet ingredients. Do not overmix, just until the ingredients are combined. Stir in the chopped toasted pecans.
Divide the batter between the loaf pans.
Place the loaf pans on a sheet pan and bake for 45-55 minutes or until a cake tester comes out clean. Cool in the pan for 15 minutes, then turn out the loaves onto a wire baking rack to cool completely.
Can be wrapped in plastic wrap or foil and kept refrigerated for 3-5 days or freeze (wrapped in freezer paper) for up to a month.