Sift the flour, baking powder, baking soda, and salt into a bowl and set aside.
In the bowl of a mixer fitted with a whisk attachment, or in a large bowl using an electric mixer on medium speed, beat the eggs and sugar until lightened to a cream color, about 2 minutes. During mixing, scrape down the sides of the bowl with a spatula as needed.
On low speed, mix in the oil and vanilla until blended.
Mix in the sour cream.
Add in the flour mixture until it is incorporated and the batter is smooth.
Stir in the cinnamon and mashed bananas.
In a muffin tin lined with cupcake liners, fill each liner with 1/4 cup cup of the batter.
Bake for approximately 25 minutes; until the top of the cupcake feels firm and an inserted toothpick comes out clean.