Tender pumpkin spice bundt cake layers with creamy vanilla buttercream and handmade pumpkin stem.
Preheat oven to 350 °F. Spray one large bundt cake pan with non-stick cooking spray. Set aside.
In a medium-size bowl, whisk and stir together the all-purpose flour, cornstarch, baking powder, salt, and pumpkin pie spice. Set aside.
In the stand mixer bowl fitted with a paddle attachment, beat the butter, oil, and sugar on medium-high for 5 minutes.
Add the eggs, one at a time to the stand mixer bowl and beat on medium until well incorporated.
Turn the mixer on low and add the flour mixture to the butter mixture until fully incorporated.
Pour in the buttermilk and vanilla extract. Mix on medium for another 30 seconds. Scrape down the sides of the bowl.
Split the cake batter in half and fill the bundt pan with one half of the cake batter (it’s approximately 13 large scoops).
Bake for about 35-40 minutes or until a toothpick inserted into the center of each cake comes out clean or with just a few moist crumbs.
Remove cakes from oven and let cool in the bundt pan for 10 minutes before inverting onto cooling racks to cool completely.
Repeat steps 8 & 9 with the remaining cake batter.
Wrap both bundt cakes in plastic wrap and place in the freezer to chill for 60 minutes.
In the stand mixer bowl fitted with the paddle attachment, beat the butter on high until light and fluffy, about 5 minutes.
Turn the mixer to low, gradually add powdered sugar, followed by the heavy cream. Then add vanilla extract and salt. Mix until incorporated completely. Scrape down the sides of the bowl.
Turn the mixer to medium-high and beat the buttercream for about 5 minutes until light and fluffy. Scrape down the sides of the bowl. Turn the mixer on low and mix for 2 minutes to push out any air bubbles.
Add 1-2 drops of orange, super red, and chocolate brown gel food coloring to color the buttercream a rustic orange.
On a silicone mat, knead the tan fondant until it’s smooth, add a small amount of shortening if fondant is too dry or cornstarch if fondant is too sticky. Repeat with the brown and green fondant.
Roll the tan fondant into a rope then split in half, cutting lengthwise. Repeat with the brown and green fondant.
Combine one-half of the tan, brown, and green fondant ropes. Then twist the colors together and combine with the other half of the colors. Continue to twist and marble the fondant together, so the fondant stem is lightly streaked with all three colors.
Roll and cut into a 4-inch log. Then use a molding tool to make vertical lines and texture similar to a real pumpkin stem. Press the end of one side to make flat to stand up on its own. Set aside to dry for one hour.
On a cake board, place one of the bundt cake ridge side down and cut the bottom off so the cake will sit flat. Keep the cake crumbs and set aside. Repeat with the second bundt cake.
Combine the cake crumbs with a dollop of buttercream, mix until you have a moist cake mixture. Set aside.
Place a small amount of buttercream onto the cake board. Layer one bundt cake, cut side up onto a cake board. Add 1 cup of buttercream over the cake and place the other bundt cake layer over the top with the ridges up.
Make the ridges on the sides, so the cakes line up perfectly. Fill the center hole of the bundt cakes with the cake mixture.
Cut off the small ridges of the bundt cakes. Cut it slightly lower than the large ridges, so it’ll create the lines for the pumpkin later.
If the center hole still needs to be filled in, then repeat the process above by mixing the cake crumbs and a small amount of buttercream.
Crumb coat with orange vanilla buttercream and freeze for 30 minutes.
Add a thick layer of orange buttercream all over the cake. Use an offset spatula to fill in any gaps with more buttercream. Then use a flexible cake smoother to smooth out the ridges of the cake. Place the cake back into the freezer for 30 minutes.
Gently press and rub a piece of micro-fiber paper towel to smooth out the cold buttercream.
Finish by adding the fondant stem on top. Serve at room temperature and enjoy!