In a cast iron skillet, cook sausage over medium-high heat, stirring occasionally, until browned and crumbly, about 5 minutes. Transfer to a plate.
Heat 1 Tbsp olive oil over medium-high heat, and cook onion and bell peppers until soft. Add chopped sweet potatoes; season with salt, black pepper, oregano. Cover and cook, stirring occasionally, until tender, about 8 minutes.
Add cooked sausage, eggs, and stir everything. Cook until bottom is set, about 2 minutes.
Bake in a preheated oven for about 5 - 7 minutes, just until set. Garnish with chopped parsley and sliced avocado, if desired.