Combine flour, baking powder, baking soda, and salt in a medium bowl and set aside.
In a large bowl, beat the eggs and sugar until thickened and lightened to a cream color, about 2 min.
Add the oil and vanilla and mix until blended.
Mix in the sour cream, then the flour mixture. Mix until the batter is smooth.
Pour into 24 regular size muffin tins lined with cupcake liners.
Bake at 350 degrees 18-23 min.
Cool completely.
Prepare frosting by combining butter, cream cheese, and vanilla in a large bowl. Beat on low speed until smooth, about 1 min.
Add the powdered sugar and cinnamon, mixing until smooth, about 1 min, then beat on medium speed for 1 min. to lighten frosting.
Spoon into a piping bag and frost cupcakes as desired.
Sprinkle generously with cinnamon and sugar.