Maple-Walnut Cupcakes

Directions

1. 1
   Preheat the oven to 350F.
2. 2
   Line two standard 12-cup muffin pans with paper liners.
3. 3
   Into a large bowl, sift together flour, baking powder, salt, and cinnamon; set aside.
4. 4
   In the bowl of an electric mixer fitted with the paddle attachment, beat the butter and sugar on medium speed until creamy, about 3 minutes.
5. 5
   Add the eggs and vanilla, and beat until combined.
6. 6
   With the mixer still on medium speed, add the flour mixture in two parts, alternating with the milk and beginning and ending with the flour.
7. 7
   Stir in the walnuts with a wooden spoon.
8. 8
   Divide the batter evenly among the muffin cups, adding about 1/3 cup to each.
9. 9
   Bake, rotating pans halfway through, until cupcakes are golden and a cake tester inserted in the center of a cupcake comes out clean, 18 to 20 minutes.
10. 10
    Transfer the pans to a wire rack to cool slightly.
11. 11
    Invert cupcakes onto the rack; then reinvert and let them cool completely, top sides up.
12. 12
    Frost tops with Maple Buttercream and garnish with Candied Walnuts, if using.
13. 13
    Cupcakes can be refrigerated in an airtight container for up to 3 days.
14. 14
    In the bowl of an electric mixer fitted with the whisk attachment, beat the egg yolks on high speed until light and fluffy, about 5 minutes; set aside.
15. 15
    In a small saucepan set over medium-high heat, bring the maple syrup to a boil, and cook until it registers 240F on a candy thermometer, about 15 minutes.
16. 16
    Remove from heat.
17. 17
    With the mixer running, slowly pour syrup down the side of the bowl in a slow, steady stream, until completely incorporated, about 1 minute.
18. 18
    Continue beating until bowl is just slightly warm to the touch, 4 to 5 minutes.
19. 19
    Add butter, one piece at a time, until thoroughly incorporated and the frosting is fluffy, about 4 minutes more.