Preheat the oven to 425°. Lightly grease a standard-size muffin tin. In a medium bowl, toss the hash browns with the butter and salt until well combined.

Place 2 tablespoons hash browns into each cup of the muffin tin. Press gently into the base to form a crust. It’s OK if the potatoes come up slightly around the edge of the cup.

Bake the hash-brown crust until it’s golden and crisp, about 12 to 15 minutes. Remove from the oven and cool slightly. Reduce the oven temperature to 375°.

Place about 1 tablespoon bacon into each crust, then top with a few pieces of tomato.

In a medium bowl, whisk the eggs with the milk and season with salt and pepper. Pour the custard into each cup, stopping about ¼ inch below the top rim. Sprinkle cheese on top and bake until the quiches are puffed up and golden, 12 to 15 minutes. Cool for 5 minutes before removing from the tin. Serve warm.