Swiss Cheese & Mushroom Quiche

A classic quiche that gets its savory depth from three places: nutty Swiss cheese on the bottom, sauteed mushrooms and onions in the middle, and a pinch each of thyme and dry mustard in the custard. The dry mustard is subtle but important. It sharpens the Swiss cheese flavor without tasting distinctly mustardy.

Blending the eggs, milk, and flour together (rather than whisking by hand) produces a custard that’s silky smooth with no lumps. The flour acts as a stabilizer that helps the custard set firmly enough to slice without being dense or rubbery.

Layering matters here. Cheese goes directly on the crust, then the mushroom-onion saute, then the custard poured over everything. This keeps the cheese from floating to the top and ensures it melts into a gooey layer at the base of every slice.

Pro Tips

• Saute the mushrooms until they release their moisture and start to brown. Wet mushrooms will make the custard watery.
• Use an unbaked pie crust. Pre-baking isn’t needed here since the quiche bakes long enough to crisp the crust through.
• The center should be just barely set when you pull it from the oven. It continues to firm up as it cools.
• This quiche works at any temperature, making it great for brunch buffets or packed lunches.

Variations

• Swap Swiss for Gruyere for an even deeper, more complex cheese flavor.
• Add a handful of fresh spinach leaves under the mushroom layer.
• Use 2 whole eggs plus 2 egg whites for a lighter version with less cholesterol.