Preheat the oven to 350 degrees. Spray the bundt cake pan with cooking spray and set aside.
In a small mixing bowl, whisk together the flour, baking powder, and salt; set aside.
In a separate bowl, combine the brown sugar, granulated sugar, vanilla, and butter. Mix together until well combined. Add the eggs one at a time, mixing well in between.
Add in the flour mixture, alternating with the milk. Mix on low speed until the batter is creamy and well combined.
Pour into the bundt pan and bake for 1 hour. Cool for about 10 minutes and invert onto a cooling rack until completely cooled.
If using the brown butter sauce, in a small saucepan, bring the butter, brown sugar, milk, and maple syrup to a rolling boil. Continue mixing for 2 minutes and remove from the burner.
Mix in the vanilla and allow to cool until thickened. Serve as a side or drizzle on top of your cake after it has cooled.
*Nutritional information is a calculated guesstimate. Please note that this can change with different brands and modifications you may make to the recipe. For the most accurate information, use a nutritional calculator with the exact brands and measurements you're using with each recipe.