-
1
For the cupcakes:
-
2
Preheat the oven to 350u00b0F.
-
3
Using a food processor with the shredding blade or the medium holes of a box grater, peel, then grate the butternut squash or pumpkin. You will need a total of 2 1/2 cups.
-
4
In a medium bowl, sift together the flour, cinnamon, nutmeg, salt, baking powder, and baking soda.
-
5
In a large bowl, whisk together the sugar, oil, sour cream, and vanilla. Add the egg and egg yolk and whisk to combine. Add the flour mixture and whisk until just combined. Using a spatula, fold the butternut squash or pumpkin into the batter. Divide the batter evenly among muffin cups.
-
6
Bake, rotating the pan halfway through, until the cupcakes spring back to the touch and a cake tester inserted in the center of a cupcake comes out clean, 20 to 25 minutes. Transfer the pan to a wire rack. Invert the cupcakes onto the rack; then reinvert, and let them cool completely, top sides up.
-
7
To make the buttercream:
-
8
In the bowl of an electric mixer fitted with the paddle attachment, beat together the cream cheese, butter, vanilla, and salt on medium-high speed until light and smooth, about 3 minutes.
-
9
Bring about 2 inches of water to a simmer in a large saucepan. Place chocolate in a heatproof bowl, and place the bowl over the pot and stir until the chocolate is melted. Slowly add the melted chocolate to the cream cheese mixture and beat to combine. Scrape down sides as necessary. If the buttercream is too soft to spread, cover and chill for 20 minutes, whipping on the mixer for 30 seconds before using.
-
10
Spread the tops of the cupcakes with the frosting, swirling to coat. The cupcakes can be kept in an airtight container in the refrigerator for up to 3 days.
-
11
Buttercream can be refrigerated for 1 week or frozen for up to 1 month. Before using, bring to room temperature and beat for a few minutes until smooth.
