Heat butter in large non-stick skillet over low heat (setting should be between rock-bottom low and medium-low, if possible). Whisk eggs, cream, salt and pepper in bowl until well incorporated.
Once butter is melted, tilt pan so butter coats all parts of the pan. Carefully pour egg mixture into pan and cover. Cook for about 5 minutes, until bottom is just set.
Assemble spinach and cream cheese on cutting board. Using a large chef’s knife, roughly chop the spinach and cream cheese, mixing to combine. Add spinach mixture to bowl, along with Parmesan and garlic. Stir with your hands. The goal is to mix ingredients well so each bite of the omelette is equally cheesy, garlicky and spinach-y.
Once bottom of omelette is set, add filling ingredients to one side of the omelette. Sprinkle red pepper flakes on top of filling.
Cover and cook about 2 minutes more, until all liquid is nearly set and outside of omelette is golden. Now, with a spatula (maybe two), carefully flip empty half of omelette over to cover the filling. If your egg layer doesn’t quite cover all of your filling, no worries.
Cover and cook 3-4 minutes more, until cheese is melted. Omelette should appear puffy.
Cut in half and serve with bacon, fried tomatoes or hashbrowns.