A comforting and flavorful baked dish combining layers of potatoes, tomatoes, and onions with a creamy cheese topping.
Preheat your oven to 350°F (175°C).
Preheating ensures even cooking from the start.
Slice the potatoes, tomatoes, and onion into thin, even slices.
Use a mandoline slicer for uniform slices.
Grease an ovenproof baking dish with a bit of butter.
Ensure the dish is well-greased to prevent sticking.
Layer the potato, tomato, and onion slices in the dish, alternating them, and finish with a layer of potatoes.
Overlap the slices slightly for a beautiful presentation.
Dot each layer with small pieces of butter and season with salt and pepper.
Distribute the butter evenly for consistent flavor.
Pour the milk over the layered vegetables.
Pour slowly to ensure even distribution.
Sprinkle the grated cheddar cheese evenly over the top.
Grate the cheese finely for better melting.
Bake in the preheated oven for 1 hour, or until the potatoes are tender and the top is golden brown.
Check doneness by inserting a knife into the potatoes; it should slide in easily.
Let the gratin rest for 5 minutes before serving.
Resting allows the layers to set and makes serving easier.