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Position an oven rack in the center of the oven and preheat oven to 400F. Butter twelve 3-by-1 ½-inch muffin cups.
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In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
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In a large bowl, beat the sugar and butter with an electric mixer on high speed until combined, about 1 minute. Beat in the egg and vanilla. Scrape down the sides of the bowl. Beat in the sour cream. Using a wooden spoon, stir in the flour mixture, until just combined. Do not overmix. Fold in the chocolate chips. Using a ⅓-cup food portion scoop or a spoon, transfer equal amounts of the batter into the prepared muffin cups. Sprinkle with the cinnamon sugar.
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Bake until the muffins are golden brown and the centers spring back when touched, about 20 minutes. Let the muffins cool in the pans on a wire cooling rack for 10 minutes. Remove from the pan and let cool completely on the rack.