From America's Test Kitchen Season 4: Sunday Brunch
A substantial Denver omelet has become a breakfast feature in American restaurants and diners. Filled with ham and lots of vegetables in addition to cheese, it’s a meal in itself. But it’s hard to get the vegetables cooked without overcooking the eggs. Cooking the filling separately, before the eggs, seemed to be the best way to avoid undercooked vegetables. In addition to the standard onion and green bell pepper, we also included red bell pepper, which made for a more colorful filling. Instead of julienning the vegetables, we finely chopped them; this made our filling easier to eat, and the peppers’ skin was less intrusive. Ham steak was the easiest kind of ham to dice: it also imparted a welcome smoky flavor to the rest of the filling. For more complexity of flavor, we included garlic and parsley, which are unusual in a Denver omelet, and a dash of hot sauce livened things up without adding too much spiciness. We cooked the eggs according to our tried-and-true method, with some dairy (we used a little heavy cream, but milk worked as well) to keep the eggs from drying out, and added the warm filling just before folding the omelet onto a plate. Both components—eggs and filling—were perfectly cooked.
Prepare the filling and then begin making the omelet. A ham steak is our top choice for the filling, although canned ham and sliced deli ham will work. (If using sliced deli ham, add it with the garlic, parsley, and hot sauce.) If you can find them, Cook’s brand ham steaks are our favorite. The filling recipe makes enough for two omelets and can be doubled. You can make one omelet after another in the same pan, although you may need to reduce the heat. For the best results, serve all omelets, including this one, on warmed plates.