Place butter in a 10-inch skillet and heat to high. Add vegetables and sauté for 1 minute. Beat eggs and water in a bowl and pour into skillet. Let cooked egg flow to edges of skillet as it is tilted. Cook the omelet and fold in half. Slide omelet onto a plate. Cut omelet in half and place each half on top of meat.
Warm omelet croissant in microwave for 30 seconds or until warm. May also return omelet croissant to skillet and grill for another minute on each side to melt cheese or use a Panini maker or griddle to heat croissants.