In a large skillet, heat the olive oil over medium heat. Add the chopped onion and minced garlic, sautéing until fragrant and the onion is translucent, about 3-5 minutes.
Add the ground beef to the skillet, breaking it apart with a wooden spoon. Cook until browned and fully cooked, about 5-7 minutes. Drain excess fat if necessary.
Stir in the diced bell peppers, chopped spinach, and cauliflower rice. Cook for an additional 3-4 minutes until the vegetables are tender.
Reduce the heat to low and mix in the softened cream cheese until well combined and creamy. Add the Italian seasoning, salt, and pepper, stirring until everything is evenly coated.
Transfer the beef mixture into a greased 9x13 inch casserole dish, spreading it evenly.
Sprinkle the shredded cheddar cheese over the top of the casserole.
Bake in the preheated oven for about 25-30 minutes, or until the cheese is melted and bubbly.
Once done, remove from the oven and let it cool for a few minutes before slicing.
Garnish with fresh parsley if desired before serving.