Preheat the oven to 375°F (190°C).
Heat the olive oil in a large skillet over medium heat.
Add the diced onion and minced garlic to the skillet and sauté for 3-4 minutes until softened.
Add the ground beef to the skillet and cook until browned, breaking it apart with a spoon, about 6-7 minutes.
Drain any excess fat from the skillet.
Add the diced zucchini, chopped cauliflower, and sliced mushrooms to the skillet. Cook for 5 minutes, stirring occasionally, until the vegetables are tender.
Stir in the dried oregano, dried basil, salt, and black pepper.
In a separate bowl, mix together the sour cream and heavy cream until smooth.
Remove the skillet from heat and stir in the sour cream and heavy cream mixture until well combined.
Transfer the beef and vegetable mixture to a 9×9-inch baking dish.
Sprinkle the shredded cheddar cheese evenly over the top.
Bake in the preheated oven for 20 minutes, or until the cheese is melted and bubbly.
Remove from the oven and let it cool for 5 minutes before serving.