Heat 1 tablespoon of olive oil over medium-high heat. Add onions and sauté for about 3 minutes.
To the onions, add peppers, zucchini, mushrooms, and seasonings. Stir to evenly distribute the seasonings. Cook for about 8 – 10 minutes, or until vegetables are cooked through.
Remove all vegetables from the pan and set aside.
Add 2 tablespoons of olive oil to the pan over medium-high heat. Add hashbrowns in an even layer. Cook for 12-15 minutes, occasionally stirring to ensure even browning.
When the hashbrowns are cooked through, lower the heat, and add the sauteed vegetables. Stir to combine.
Add spinach and stir gently to combine. Cook until spinach is just wilted.
Evenly top with cheese and green onions, then serve.