Preheat your oven to 375°F (190°C). Lightly grease a baking dish with olive oil.

In a pot of salted water, boil the diced sweet potatoes until fork-tender, about 10-15 minutes. Drain and set aside.

In a skillet, heat olive oil over medium heat. Add minced garlic and sauté for 1 minute. Add the chopped spinach and cook until wilted, about 2-3 minutes. Remove from heat and let cool slightly.

In a large bowl, combine ricotta cheese, half of the mozzarella cheese, Parmesan cheese, eggs, oregano, salt, and pepper. Mix well.

Gently fold in the sweet potatoes and sautéed spinach into the cheese mixture. Ensure everything is evenly coated.

Transfer the mixture to the prepared baking dish, spreading it evenly.

Sprinkle the remaining mozzarella cheese over the top of the bake.

Place in the oven and bake for 30-35 minutes, or until the top is golden and bubbly.

Remove from the oven and allow the baked dish to cool for about 10-15 minutes before slicing.