Preheat your oven to 350ºF (176ºC) and grease a muffin pan with the oil.
In a pan over medium-high heat, cook the sausage until no longer pink, about 5 to 8 minutes. Break it up into little pieces as it cooks. Drain the excess drippings from the pan and stir in the spinach. Cook until the spinach has wilted then remove the pan from heat to let cool slightly.
In a mixing bowl whisk the eggs together with the water and sea salt. Fold in the green onion.
Divide the sausage mixture evenly into the muffin tins and pour in the egg mixture. Bake for 15 to 18 minutes until the egg is firm to the touch and just brown around the edges. Let the egg muffins cool slightly before removing from the pan. Enjoy!