Gridiron Sheet Cake

Preheat the oven to 375 degrees F (190 degrees C). Grease a jelly roll pan. (Prep time: 5 minutes)

In a large saucepan, bring water, butter, and cocoa powder to a boil. Remove from heat and stir in flour, white sugar, and salt. (Cook time: 8 minutes)

In a separate bowl, beat eggs, sour cream, and baking soda. Stir this mixture into the flour mixture until just blended. Pour batter into the prepared jelly roll pan. (Prep time: 7 minutes)

Bake in the preheated oven until a toothpick inserted into the center comes out clean, approximately 20 to 22 minutes. Let cake cool completely. (Bake time: 22 minutes)

While the cake is cooling, prepare the frosting. In a large bowl, cream together the softened butter, shortening, and vanilla extract. Gradually blend in confectioners' sugar, 1 cup at a time, beating well after each addition. Add milk and continue beating until frosting is light and fluffy. (Prep time: 15 minutes)

Divide the frosting into 3 bowls. Mix cocoa powder into the first bowl for a chocolatey frosting. Mix green food coloring into the second bowl for the 'field' frosting. Leave the third bowl plain. Fill 3 piping bags with the chocolate, green, and plain frosting; attach round tips. (Prep time: 10 minutes)

Use a ruler to measure out equal 'end zones' on each side of the cooled cake. Use a skewer or toothpick to poke a few holes to mark the boundaries. (Prep time: 5 minutes)

Pipe a large green square 'playing field' between the end zones. Cover the entire square with green frosting and smooth it out using a small offset spatula. (Decorating time: 10 minutes)

Create the end zones by piping a rectangle on one side of the field with chocolate frosting. Fill the rectangle with frosting and smooth it out with a clean offset spatula. Repeat on the other side of the field using the plain buttercream. (Decorating time: 10 minutes)

Place the cake in the freezer for 1 hour to firm up the frosting. In the meantime, prepare the decorations. (Freezing time: 60 minutes)

To make the goalposts, stack 3 caramel candies and secure them together with chocolate frosting. Snap 1 pretzel stick in half and use chocolate frosting to glue one half to each end of a full stick. Adhere this to the top of the caramels with more frosting. Repeat to make another goalpost. (Prep time: 15 minutes)

Sort the gummy bears into 2 sets based on team colors. (Prep time: 5 minutes)

Fill a mug with boiling water and place the offset spatula inside to warm it. Remove the cake from the freezer. Thoroughly dry the spatula and use it to smooth any lumpy frosting on the cake. Repeat as needed to keep the spatula warm. (Prep time: 5 minutes)

Carefully plot out chalk lines for the field using a ruler and toothpick or skewer. Draw 6 dotted lines 1 inch apart. Carefully cover all of the dotted lines with white chocolate chips. (Decorating time: 20 minutes)

Line each end zone with dark chocolate chips to create a border with the field, leaving room for the goalposts in the middle. Arrange the gummy bears on the field to represent the competing teams. (Decorating time: 15 minutes)