Preheat the oven to 350°F. Grease a nonstick mini muffin pan with cooking spray.
In a medium bowl, whisk together the flour, baking powder, baking soda and salt. Set the mixture aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat together the butter, vegetable oil and 1/2 cup sugar until well combined, about 2 minutes. Add the egg and beat until combined.
Add the flour mixture, sour cream and vanilla extract and beat just until combined.
Using a small ice cream scoop (or two spoons), scoop out heaping 1-tablespoon portions of the batter into the prepared muffin pan.
Bake the muffins for 16 to 22 minutes until pale golden. While the muffins bake, in a medium bowl, whisk together the remaining 1/2 cup sugar and cinnamon.
Remove the muffins from the oven and let them cool for 2 minutes in the pan before transferring them in batches into the cinnamon-sugar mixture, tossing to coat. Repeat the coating process with the remaining muffins then serve.