Crustless Spinach Quiche Recipe With Bacon

bacon, cooked and chopped, (( 226.7 g))

bag frozen spinach, thawed and squeezed dry, ((453.5 g))

large eggs

onion, thinly sliced or minced, ((about 1/4 of a medium onion) (56.5 g))

heavy cream ((177.4 ml))

Swiss or cheddar cheese, grated ((226.7 g))

salt

pepper

nutmeg

lemon zest (optional)