Preheat oven to 350 degrees and line a muffin tin with cupcake liners. In a large bowl, blend together the eggs, butter, yogurt and milk then slowly add in the dry cake mix and blend until a smooth batter forms. Divide the batter evenly between the cupcake liners and bake for 15 minutes, until golden brown.
To make the frosting, in a medium sized bowl, combine the butter and yogurt and the dry frosting mix and blend until smooth. Add blue food dye and blend until frosting becomes desired shade of blue.
In a small bowl, mix together the cocoa powder and water until blended and smooth. Use a pastry brush and dip the tip into the cocoa powder mixture, then hold the brush a few inches above the cupcakes and tap the handle to speckle the frosting to look like a Robin's egg. Top with an organic OCHO Organic Peanut Butter Egg.