For the cake

1. Preheat the oven to 350°F. Line the 6-inch pans with parchment paper or grease and flour the edges.
2. Combine the sugar with the wet ingredients: In a large mixing bowl, combine the sugar, vegetable oil, eggs and vanilla extract. Beat on medium speed until the eggs and oil are well incorporated and the batter is lighter in color. Next, mix in the sour cream and beat until well combined.
3. Combine the dry ingredients: In a separate bowl, sift together the dry ingredients. Alternate adding half of the dry ingredients and half of the milk at a time. Mix until well combined, then use a spatula to scrape down the sides of the bowl and stir the batter to ensure it’s well mixed.
4. Fill the pans: Divide the batter evenly between the pans, about 1 1/4 cups batter per pan.
5. Bake at 350°F for 20-24 minutes. Test the cake for doneness by inserting a toothpick into the center of the cake. If the toothpick comes out clean, the cake is done. Cool completely prior to frosting.

For the frosting

1. Chill the mixing bowl: Place the mixing bowl and whisk attachment in the freezer for 5 to 10 minutes to chill.
2. Combine mascarpone and cream: Spoon the mascarpone cream into your bowl and beat on a medium-low speed (speed 3 on a stand mixer). Slowly pour in the heavy cream, about 1 cup, allowing the mascarpone cheese to turn to a liquid consistency. Add the remaining heavy cream then increase the mixing speed to high (speed 8-10) and beat it until soft peaks form.
3. Set aside: Remove 1/4 cup of frosting for the mouth. Add just a drop of black food gel and stir until combined. Set aside in the refrigerator. 
4. Finish the frosting: Next, add the powdered sugar, vanilla extract and blue gel color. Beat on low until sugar is incorporated then continuing beating at a high speed until stiff peaks form. 

To assemble

1. Level the cake: Make sure they’re flat on top. Use a cake level or serrated knife
2. Stack the layers: Use ¼- ½ cup of frosting between each layer and spread evenly.
3. Add the structure: Once all the layers are stacked, take 3 plastic straws, and cut them just short of the height of the cake. Place them in a triangular pattern.
4. Crumb coat the cake: First apply a very thin crumb coat on the outside of the cake. Smooth with an offset spatula or bench scraper.
5. Fill 4-5 small piping bags: With the remaining frosting, fill bags only 2/3 full and tie off the end with a rubber band. Keep refrigerated. When ready to use, cut off the tip of the bag. 
6. Cut out the mouth: First make the top cut. Angled it like a half moon and cut at about a 45-degree angle. Then on the bottom, cut upwards at a 45-degree angle, meeting the edges of the upper part of the mouth. Remove the piece of cake. Fill with black frosting. 
7. Prepare the second piping bag: Assemble a small piping bag with a coupler and a grass tip, and then drop one of the frosting filled piping bags inside. 
8. Decorate: Start piping along the bottom edge and working in a circle around the cake. Start the next layer just slightly above and pull the frosting downward so it sits overtop of the bottom layer. Repeat until the side of the cake are frosted
9. Frost the top:To frost the top, start from the outside edge and working in a circle until you reach the middle.
10. Place the eyes: Do this right before serving.