"Create a steak and pearl onion frittata using olive oil, pearl onions, salt, pepper, eggs, finely diced steak, dairy-free butter, and fresh parsley. The user wants a good substitute for heavy cream and a substitute for shredded parmesan or asiago cheese. Make it gluten-free, dairy-free, nut-free, soy-free, sesame-free, corn-free, minimal processing, beginner-friendly, and suitable for a quick 15-30 minute meal. Use imperial units only. Include the best substitutes directly in the recipe: for heavy cream, use unsweetened full-fat coconut milk or canned coconut cream; for parmesan/asiago, use nutritional yeast if appropriate, or a dairy-free parmesan-style topping made from seeds is NOT allowed because of sesame/nuts, so prefer nutritional yeast plus extra salt and a little lemon zest if needed. Keep it simple and accurate."