First, preheat the oven to 350° Fahrenheit, and line two cupcake pans with paper cupcake liners. Then, make the cupcakes! In a medium bowl, whisk together the flour, almond flour, baking powder, and salt, then set aside. In a large bowl, whisk together the eggs, sugar, oil, vanilla, sour cream, and milk until smooth. Add in the whisked dry ingredients and stir together until combined.
Then, make the cinnamon swirl. In a cereal bowl or other small bowl, whisk together the melted butter, brown sugar, cinnamon, vanilla, and flour until smooth and fully combined.
To layer the cupcakes, spoon only two teaspoons of the plain batter into each cupcake cup, then spoon about 2-3 teaspoons of the cinnamon swirl mixture on top of that base. Then, finish filling up the cupcake cups with the plain batter (there will be a layer of the cinnamon swirl inside). Cupcakes should be about 3/4 of the way full. Bake for 17-22 minutes or until the top bounces back when touched.
Let cupcakes cool completely before frosting. While cupcakes are cooling, make the frosting! In a large bowl, using an electric mixer, beat together the room temp butter and the cream cheese until smooth. Add in the powdered sugar and vanilla and continue to beat until creamy and smooth. If you want to make dual-colored frosting, spoon out 1/2 of the frosting mixture in a line onto a large piece of plastic wrap, and then roll it into a log. Then, for the remaining frosting, add in the brown sugar and cinnamon and beat until combined. Then spoon out the cinnamon frosting onto another piece of plastic wrap and roll into a log. Snip off the ends of both logs and then put both logs into a piping bag and shake down until the two are parallel next to each other and will pipe out together in a swirl. Pipe on cooled cupcakes and then serve!