Apparently, no one knows - see http://www.recipelink.com/cookbooks/2004/0811839605_1.html

My top 3 guesses would be Bob Denver, John Denver, or Denver Pyle.

Looks like the origin is at question. Denver Omelet Recipe from: Cooking USA by Georgia Orcutt and John Margolies Cookbook Heaven at Recipelink.com The origin of this popular dish remains a mystery, but it has been known around Colorado's capital city and beyond for decades. A favorite for a truly hearty Western-style breakfast, this oven-baked omelet is also eaten for dinner. To make it even richer, use half-and-half instead of milk. Makes 4-6 servings 2 tablespoons butter 1 medium onion, chopped 1 green or red bell pepper, seeded and chopped 1 cup chopped cooked ham 8 eggs 1/4 cup milk 1 cup (4 ounces) grated cheddar cheese Salt and freshly ground black pepper Heat the oven to 400 degrees F. Grease a 10-inch round baking dish (or make the entire recipe in a cast-iron skillet). Melt the butter in a skillet over medium-low heat. Add the onion and bell pepper and cook for about 5 minutes, stirring occasionally, until soft. Add the ham and cook for 2 minutes more. Remove from the, heat. Beat the eggs and milk in a large bowl. Stir in the cheese and add the sauteed vegetables and ham. Season to taste with salt and pepper. Transfer the mixture to the prepared dish. If baking in a cast-iron skillet, pour egg mixture with cheese over the vegetables and ham. Bake for 20 minutes or until the top is puffy and brown. Cut into wedges and serve warm. --------------------------------------------------------------------------------