Whisk together the egg, cream, salt, pepper, onion powder, and parmesan. Set this bowl aside near your stove.
Step 2
Choose a pan that is the same size as your omelette. Heat the olive oil on a medium-low heat and toss in the drained tuna. Place a lid over the pan to maintain any splatter as the tuna crisps in the pan. You can adjust the heat as necessary to avoid a mess. Cook for 2-3 minutes while breaking up the tuna into bits and pieces.
Step 3
Turn the heat down low and pour your egg over the tuna. Return the lid to the pan and cook until your omelette is cooked through. You may flip once to get even browning on both sides. Adjust the heat higher or lower as necessary to cook the egg without burning it in the pan.