Reprinted with permission from Bite-Size Desserts by Carole Bloom. Published by John Wiley & Sons, Inc., Hoboken, NJ. Copyright 2009. All rights reserved.

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Cinnamon-Sour Cream Cupcakes

The rich warmth of cinnamon and the slight tartness of sour cream give these little cakes distinctive flavor. They are frosted with whipped, intensely flavored bittersweet chocolate ganache and dusted on top with a mixture of cocoa powder and cinnamon. These are just right for dessert, afternoon tea or coffee, or anytime you would like a little treat.

Makes 2 dozen cupcakes
Use two 12-cavity 2-inch round silicone mini muffin pans

4 ounces (8 tablespoons, 1 stick) unsalted butter, softened
3/4 cup (5 ounces) granulated sugar
1 extra-large egg, at room temperature
1 extra-large egg yolk, at room temperature
1/2 teaspoon pure vanilla extract
1 cup plus 2 tablespoons (5 ounces) cake flour
2 teaspoons ground cinnamon, divided
1 teaspoon baking powder
1/4 teaspoon kosher or fine-grained sea salt
1/2 cup plus 2/3 cup sour cream
5 ounces bittersweet chocolate (62 to 72% cacao content), finely chopped
2-1/2 ounces (5 tablespoons) unsalted butter, cut into small pieces
1/4 teaspoon unsweetened cocoa powder

CUPCAKES:
Position a rack in the center of the oven and preheat the oven to 350°F. Place the mini muffin pans on a baking sheet.

Beat the softened butter in the bowl of an electric stand mixer with the flat beater attachment or in a large mixing bowl using a hand-held mixer on medium speed until it’s fluffy, about 2 minutes. Gradually add the sugar and beat until creamy, about 1 minute.

In a small bowl, use a fork to lightly beat the egg, egg yolk, and vanilla together. Add to the butter mixture in 2 stages, beating well after each addition. Stop and scrape down the sides and bottom of the bowl with a rubber spatula. The mixture may look curdled as the eggs are added, but as you stop and scrape down the bowl, the mixture will smooth out.

Over a medium-size bowl, sift together the cake flour, 1-1/4 teaspoons of cinnamon, and baking powder. Add the salt and toss to blend. Add half of this flour mixture to the butter mixture and blend thoroughly. Add 1/2 cup of sour cream and blend until smooth. Add the remaining flour mixture and blend thoroughly.

Bake the cupcakes for 15 to 18 minutes, until light golden and a cake tester inserted in the center comes out clean. Remove the baking sheet from the oven and cool the mini muffin pans on racks. Invert the pans to remove the cupcakes, then turn them right-side up.

BITTERSWEET CHOCOLATE GANACHE FROSTING:
Place the chocolate and the butter pieces in a medium-size microwave-safe bowl. Melt on low power for 30-seconds to cool. Add the remaining 2/3 cup of sour cream and 1/2 teaspoon of cinnamon and blend thoroughly. Cover the bowl with plastic wrap and chill for 20 minutes.

Whip the ganache in the bowl of an electric stand mixer with the flat beater attachment or a large mixing bowl using a hand-held mixer on medium speed until it holds soft peaks, about 1 minute.

Fit a 12- to 14-inch pastry bag with a large open star tip and fill it part way with the ganache. Pipe rosettes on top of each cupcake, filling the tops.

GARNISH - Sift the remaining 1/4 teaspoon of cinnamon and the cocoa powder together in a small bowl. Sift the cocoa-cinnamon mixture over the tops of the cupcakes. Serve the cupcakes at room temperature.

KEEPING - Store the unfrosted cupcakes between layers of waxed paper in a single layer in an airtight plastic container at room temperature up to 4 days. To freeze up to 4 months, wrap the container tightly in several layers of plastic wrap and aluminum foil. Use a large piece of masking tape and an indelible marker to label and date the contents. If frozen, defrost the cupcakes overnight in the refrigerator and bring to room temperature before serving.

The frosted cupcakes can be kept tightly covered in the refrigerator up to 3 days. Serve at room temperature.

STREAMLINING - The ganache can be made up to 3 weeks in advance and kept in an airtight container in the refrigerator. Bring it to room temperature or soften it in a microwave oven on low power before whipping.