Preheat oven to 350°F. Generously coat a 10- cup Bundt pan with non-stick baking spray. Sift the dry ingredients together in a medium bowl, set aside.

In the bowl of an electric mixer, begin to paddle the soft butter. Add the sugar, brown sugar, and orange zest and paddle on medium-high speed until light and fluffy.

Stop and scrape down the bowl several times throughout mixing. Add the eggs one at a time, mixing until fully combined before adding the next. With the mixer running, stream in the vegetable oil. Once the oil has been incorporated, turn the mixer to high and mix for 2 minutes. The batter should be extremely light and fluffy.

Add vanilla and about half the rum, mix until incorporated and then add the remaining rum. Alternate adding the dry ingredients (in 3 additions) and the sour cream (in 2 additions), starting and finishing with the dries, and each time mixing on low, just until mostly combined. Scrape down the bowl, and mix for about 15 seconds until fully combined.

Transfer into the Bundt pan, and bake until a wooden skewer inserted in the center of the cake comes out with no more than a few moist crumbs clinging to it, 70-80 minutes. While the cake cooks, make the syrup.

Combine first 4 ingredients in a medium saucepan. Bring to a boil and then reduce to a simmer. Stir in spiced rum and Frangelico, and simmer for 3-5 minutes. Keep in a warm place until cake comes out of the oven.

Allow cake to cool 10-20 minutes. Run a long off set spatula around entire perimeter of pan to ensure cake is loose and will unmold easily. Unmold onto a serving plate/cake platter. Using a fork or skewer, punch holes all across the top of the cake. Spoon/brush the syrup over the cake, a little at a time, and let stand until it completely absorbs into the cake. If the glaze starts to pool at the base of the cake, use a small metal spatula to spread it up and around the sides of the cake. As the glaze hardens, it will encase the cake in a sugary shell. Allow to cool completely before cutting into wedges.

For a decadent plated dessert, serve the rum cake warm and topped with candied pecans or walnuts, a scoop of butter pecan ice cream and additional Frangelico Syrup. The cake will pair well with many ice cream choices, try Vanilla Bean, Caramel, Maple, Cinnamon, or Nut flavored of any type! Also a great snack at room temperature, or simply topped with a dollop of whipped cream.