Heat a medium-sized skillet on medium-high heat. Add the olive oil and swirl to evenly coat pan.
Add the chopped onions and minced garlic to the pan; cook stirring occasionally until onions are translucent, about 5 minutes.
Add the cubed ham to the pan and cook, stirring occasionally for 1 minute. Add the spinach and stir until spinach is beginning to wilt, about 3 minutes.
Remove pan from the heat and set aside.
In a medium-sized mixing bowl, whisk together the eggs, cream, salt and pepper. Fold in the spinach and ham mixture.
Stir in the cheese and pour into lightly greased 5-inch baking dish or dish of a similar size.
Bake until quiche is puffed and golden, about 25 minutes
Notes
Sautéing: For maximum flavor, sauté your onions and garlic until they reach a tender consistency.
Mixing: Whisk the eggs and heavy cream thoroughly to achieve that silky-smooth custard texture, which is a hallmark of a great quiche.
Baking: Keep an eye on the quiche as it bakes. You'll want to remove it from the oven as soon as the center is set to preserve its moist, creamy texture.