Preheat the oven to 425 F (218 C). Line a baking sheet with parchment paper. Clean and dry 2 - 3 medium sweet potatoes. Pierce the sweet potatoes 5 - 6 times all around the potato. Roast for 40 - 45 minutes or until fork tender. Cool to room temperature, scoop out the sweet potato flesh into a food processor. Blend until smooth. Measure out 2 cups of pureed sweet potato.
3 large sweet potatoes
Reduce the oven to 350 F (177 C). Lightly grease and line a 9 x 13 pan with parchment paper along the bottom and two longer sides.
In a large bowl, whisk together the flour, baking powder, baking soda, ground cinnamon, ginger, nutmeg, cloves, all spice and salt together until well combined. Set aside for now.
2¾ cup (330 g) all purpose flour, 1 tablespoon ground cinnamon , 2 teaspoons ground ginger, ½ teaspoon ground nutmeg, ½ teaspoon ground cloves, ½ teaspoon all spice, 1 teaspoon baking powder, 1 teaspoon baking soda, ½ teaspoon salt
In another bowl whisk the oil, light brown sugar, sugar, eggs, cooled sweet potato puree and vanilla extract together until smooth and well combined. Whisk the dry ingredients into the wet well combined with no visible pieces of flour.
1¼ cup (250 g) light brown sugar, ½ cup (100 g) granulated sugar, 1 cup (240 ml) canola or vegetable oil , 3 large eggs, room temperature, 2 teaspoons (10 ml) vanilla extract
Evenly pour the sweet potato spiced cake batter into the prepared pan. Bake the cake for 30 - 40 minutes. The crust will be golden brown and the top should bounce back when gently pressed. A toothpick inserted into the center of the cake should come out with a few moist crumbs.
Cool the cake in the pan until fully cooled to room temperature. If you would like to frost and serve the cake on another serving plate, use the parchment paper to remove the cake from the pan.
While the cake cools, make the cinnamon cream cheese frosting. Cream together the butter with the room temperature cream cheese until just combined, about 2 - 3 minutes. Add the cinnamon, vanilla extract and salt. Mix until creamy and well combined, about 2 - 3 more minutes on low speed. Mix in the sifted powdered sugar.
8 oz. (226 g) cream cheese, room temperature, ½ cup (113 g) unsalted butter, room temperature, 2 teaspoons ground cinnamon , 1 teaspoon vanilla extract , 4 cups (480 g) powdered sugar, 1 - 2 tablespoons (15 - 30 ml) milk, as needed
Once all the sugar has been added, mix on high until the cream cheese cinnamon buttercream is fully incorporated and your desired consistency. Top the cooled cake with the frosting. If you would like, add some crunchy nuts like chopped pecans or walnuts.
½ cup chopped pecans or walnuts, optional