Preheat oven to 325 degrees.
Spray a standard size bundt pan generously with non-stick cooking spray.
In a saucepan, combine butter, water and salt and heat over medium heat, stirring until butter has melted and combined with water. Remove from heat and set aside.
In a mixing bowl, combine flour, sugar and baking powder and stir to blend. Pour in half of your melted better and water mixture, and stir well to combine. Pour in remaining melted butter and water, stirring until well combined. Add in one egg and vanilla, stir until well combined. Add in remaining egg, stir until well combined. Finally add in your Greek yogurt, stirring until well combined. Batter will be thick.
If coloring your cake batter, divide your batter in as many bowls as desired for colors, and add in your food coloring to each bowl, stirring until color is well combined through out.
Pour into your bundt pan sprayed with cooking spray (one color at a time if using multiple colors - do not mix them once in the bundt pan, just pour one color on top of the next). Place in oven and bake until a toothpick inserted into the center comes out clean, approximately 50-60 minutes.
Remove from oven and allow to cool on a wire rack for approximately 15 minutes, then carefully remove cake from bundt pan and allow to cool for another 15 minutes.
Frost with your favorite frosting. To create a multi colored frosting, divide your frosting into multiple bowls and add your desired food coloring. Once your frosting is mixed, place your bowl in the microwave from 5-10 seconds - you just want to heat it enough to melt it a bit to make it easy to drizzle on your cake. Stir well after removing from the microwave then drizzle onto your cake with a spoon, and repeat with all of your colors. Enjoy!