Steps
1. Preheat your oven to 350°F (175°C).
2. In a skillet, heat olive oil over medium heat. Add the diced onions and sauté until translucent, about 3 minutes.
3. Add sliced mushrooms and cook until they are browned, about 5 minutes.
4. Stir in the chopped spinach and cook until wilted, about 2 minutes.
5. In a bowl, mix the mayonnaise, garlic powder, paprika, salt, and pepper until well combined.
6. Add the sautéed vegetables to the mayonnaise mixture and fold in the sliced olives.
7. Transfer the mixture to a small baking dish, spreading it evenly.
8. Bake in the preheated oven for 15-20 minutes, or until heated through and slightly golden on top.
9. Garnish with fresh parsley if desired and serve hot.