"Create a from-scratch, dairy-free, corn-free, wheat-free version of restaurant-style hashbrown casserole inspired by the linked recipe. Make it suitable for a beginner cook, quick and easy, minimal processing, low-inflammation friendly, and sized for a household of 3. Use only safe ingredients avoiding gluten, dairy, nuts, shellfish, soy, sesame, and corn. Include imperial units only. Keep it as close as possible to the classic creamy hashbrown casserole texture and flavor, but make all components from scratch (no canned soup, no packaged cream soup, no corn-based ingredients)."