Preheat oven to 325 degrees. Using your hands, evenly spread 1 Tbs of butter around the bottom and up the sides of a 10 inch cast iron skillet. Sprinkle with 2 Tbs of flour and evenly distributed.
In a medium bowl, whisk eggs and blend in oil and water, mix until incorporated. Gently stir in Foodstirs Chocolate Lovers Brownie Mix until batter is thick. Pour batter into prepared skillet and evenly spread. Bake 19-22 minutes or until a toothpick inserted in the center comes out clean. Allow to cool completely on a wire rack.
For the frosting, in a medium bowl cream butter and yogurt using a hand mixer until smooth. Slowly blend in 2 packages Organic Vanilla Frosting Mix and beat on medium speed 1-2 minutes or until mixture is smooth.
Divide frosting into 5 bowls by measuring 1 cup of frosting into two of the bowls. In the third bowl place 1/2 cup of frosting, then divide the remaining frosting in half, distributing between the last two bowls. In a bowl with 1 cup of frosting, add 1 packet of Color Kitchen Bright Blue dye and 1 Tbs DecoPack natural yellow dye. Mix until the frosting becomes a bright green color.
In the second bowl with one cup of frosting, add the red Color Garden dye and stir until the frosting becomes a cherry red color. To one of the bowls with the divided frosting amount, add the Color Garden brown dye and mix until full incorporated. To the second bowl with the divided frosting amount, add the packet of Color Kitchen yellow dye, mix until the frosting becomes a bright yellow color. The bowl with 1/2 cup of frosting remains white.
Set the green frosting aside, then place each remaining color of frosting into its own piping bag, using a star tip for the piping bag with white frosting, and a flat tip for the piping bag with the red frosting. Using a scissors, cut off the tips of the piping bags with the brown and yellow frosting.
Using a spatula, spread the green frosting evenly over the entire brownie. Pipe the red frosting across the top 1/3 of the skillet to then pipe a few curved lines down the right side of the skillet to complete the Santa hat.
Using the white frosting piping bag, pipe the trim of the Santa hat across the skillet, where the green and red frosting meet then make the pom pom at the end of the hat by piping a small circle.
Pipe ovals with the yellow frosting for the Grinch's eyes, then line them with the brown frosting. Make two diagonal lines for the eyebrows, then pipe a small circle and a line straight down for the nose. Still using the brown frosting, pipe curved lines up for a smile, then two semi circles on either side of the Grinch's cheeks.