Heat the olive oil in a large heavy skillet and cook the onion and garlic until crisp-tender, about 5 minutes, stirring frequently.
Add the chopped spinach to the skillet and cook, stirring often, until the spinach is tender, about 5 to 7 minutes. Be sure to cook this until the water that leaches out of the spinach has evaporated.
In a medium bowl, beat the heavy cream with the eggs, salt, pepper, and thyme until foamy.
Add the egg mixture to the skillet and cook and stir so the eggs scramble with the spinach, about 4 to 5 minutes longer. Sprinkle with the cheese and serve.