Preheat oven to 350F.2.3. 4. 5. 6.7. 8.
Grease a 10 or 12-cup Bundt pan with cooking spray.
In a medium bowl, whisk flour, baking powder, salt, nutmeg, and cinnamon until well combined.
Beat butter and sugar until smooth. Add olive oil, and keep whisking. Then, add eggs one at a time, fully incorporating after each addition. Add rum and vanilla at this point if using.
Using a spatula, stir in dry ingredients first and then eggnog. Do not over-mix.
Bake for 45 mins or until a toothpick inserted into the center comes out mostly clean.
Place cake on a wire rack to cool.