8 tablespoons (1 stick) unsalted butter, room temperature, plus more for pan
1 2/3 cups all-purpose flour, plus more for pan
1 teaspoon ground cinnamon
1/4 teaspoon ground nutmeg
1/4 teaspoon ground allspice
1/2 teaspoon salt
1/2 teaspoon baking powder
1/2 teaspoon baking soda
1 1/2 cups sugar
2 large eggs
1 cup pumpkin puree
1/2 cup warm (110 degrees) milk
Heat the oven to 350 degrees. Butter a 9-by-2-inch round cake pan. Line pan with parchment, and butter the parchment. Coat pan with flour, and tap out any excess.
In a large bowl, sift together flour, cinnamon, nutmeg, allspice, salt, baking powder, and baking soda; set aside.
In the bowl of an electric mixer fitted with the paddle attachment, beat sugar and butter together until light and fluffy, about 2 minutes. Add eggs, and beat until combined. Add pumpkin puree and milk; beat until combined. Add reserved flour mixture; beat on low speed until just combined.
Pour batter into prepared pan, and bake until a cake tester inserted into the middle comes out clean, about 55 minutes. Transfer the cake to a wire rack to cool. Let cake rest 20 minutes.
Unmold cake. Using an offset spatula, spread icing over top of cake, and decorate with caramelized walnut halves.
In a small saucepan, melt butter over medium-high heat until nut-brown in color, about 10 minutes. Remove pan from heat, and pour butter into a bowl, leaving any burned sediment behind.
Add sugar, vanilla, and 1 tablespoon milk; stir until smooth. If the icing is too thick, add the remaining tablespoon milk, a little at a time, until consistency is spreadable. Let cool 5 minutes. Use immediately
In a small skillet, melt sugar over medium-high heat until medium golden, about 3 minutes. Remove skillet from heat. Working quickly, drop walnut halves, one at a time, into the melted sugar. If the sugar hardens, return skillet to low heat, and stir several minutes. Using a fork, turn walnuts until they are evenly coated. Transfer walnuts to a wire rack to cool completely. Use to decorate cake.
-I made this cake a day in advance, wrapped it up in plastic wrap and it was still super fresh & moist the next day!
-I used salted butter for the icing! It tasted AWESOME.