Heat oven to 350°F. With nonstick spray, coat standard-size muffin pan, 2-1/2 x 1-inch cups.
Whisk flour, cocoa powder, cinnamon, baking powder, baking soda, salt and nutmeg in large bowl.
In large bowl, beat butter on medium until smooth, 1 minute. Gradually beat in sugar; then beat on medium-high 3 minutes or until fluffy. Add eggs, one at a time, beating well after each addition. Beat in vanilla. On low, beat in flour mixture alternately with sour cream in 3 additions, beginning and ending with flour; beat 2 minutes. Fold in chocolate and nuts. Fill muffin cups half-full.
Bake in 350°F oven 15 minutes or until tops spring back when touched. Cool cakes in pan on rack 10 minutes. Turn cakes out onto rack; cool. Repeat with rest of batter.
Bring cream to boiling in small saucepan. Place chocolate in small bowl. Pour hot heavy cream over chocolate; stir until smooth.
Place wire racks over jelly-roll pan. Place cakes, large, flat-side down, on racks. Pour about 2 tablespoons ganache evenly over each cake to cover completely; smooth ganache with small spatula.
Garnish each cake with 2 or 3 almonds if desired. Refrigerate for 1 hour or until ganache is firm.