Cake: In a large mixing bowl, beat together the butter, sugar, spices and baking powder. Add one egg and beat until smooth. Scrape the bowl and add the remaining eggs, one at a time, beating until the mixture is smooth and fluffy after each egg is added.
Add the flour, about 1/3 at a time, alternately with the liquids (milk and bourbon). Be sure to scrape the bottom and sides of the bowl after each addition. Blend in the nuts, if you're using them.
Grease and flour your pan(s); use one (2.8L, 11 cup) bundt-style pan, a 10-inch tube pan, or two 8 1/2 x 4 1/2-inch loaf pans. Preheat your oven to 180°C
Scoop the batter into the pan(s) and level it with a spatula. Bake the cake for 70 to 75 minutes, until a tester inserted in the center comes out clean. Remove the cake from the oven, and let it cool it in the pan(s) for 10 minutes.
Syrup: While the cake is cooling, heat the butter, sugar and bourbon together in a small saucepan set over low heat. Stir until the butter is melted and the sugar is dissolved, then bring the mixture to a boil. CAUTION: The bourbon is likely to burst into flame when it reaches the boiling point. This process, while quite impressive, calls for a few notes of caution. Don't lean over the pan while you're stirring; it also might be a good idea to have a lid handy to quiet the flame. This process will burn off the alcohol. When the flame goes out, remove the glaze from the heat. Note: the bourbon may not ever burst into flame; that's OK. Just boil it for about 15 seconds, then remove it from the heat.
After the cake has cooled for 10 minutes, turn it out of the pan and onto a rack, then poke small toothpick-sized holes all over the top surface. Brush the top of the cake with the still-warm glaze. It'll drizzle down into the holes to make a very moist cake.
You can certainly eat the cake as soon as it's cooled, but it does improve with a "rest period" of 1 or 2 days. Do let the cake cool for several hours, to allow the glaze to set before wrapping well in plastic wrap. (No need to refrigerate it.) Before serving, dust the cake with a non-melting sugar, if desired, or ice with Bourbon White Chocolate Ganache. Yield: one cake or two "loaves," about 32 servings.