This crustless spinach quiche is one of those dishes I turn to when I want something that feels special but doesn't demand a full day in the kitchen. I first developed this version during a busy holiday weekend when I needed something that would feed a crowd, fit a gluten-free diet, and be easy to transport. The combination of sharp cheddar and tangy feta gives every bite a lively contrast, while the tender, eggy custard keeps it light and fluffy. It quickly became a staple for weekend breakfasts, packable brunches, and even a simple dinner with a big salad.

What I love most about this dish is how forgiving it is: the onion and mushroom base adds savory depth, the spinach brings color and nutrients, and the cheeses provide both creaminess and bite. Because there’s no crust to fuss over, the whole preparation is faster and cleaner. Family and friends frequently ask for the recipe after tasting it warm from the oven, and I always feel proud serving slices that hold neatly and stay moist the next day. This version yields about 6 generous slices from a 9-inch deep-dish pie plate and comes together in roughly 60 minutes total.

Ingredients

• Sweet onion: 1 small, finely diced. Choose a mild variety like Vidalia or Walla Walla when possible—these caramelize beautifully and add a sweet foundation without sharp sulfur notes.
• Mushrooms: 4 ounces, thinly sliced. Cremini or white button mushrooms work well; they add an earthy, meaty texture that pairs with the cheeses.
• Garlic: 2 cloves, minced. Fresh garlic brightens the savory base—use more or less to taste.
• Frozen chopped spinach: 10 ounces, thawed and thoroughly drained. Squeeze or press out excess moisture to avoid a watery custard; use a fine-mesh sieve or clean dish towel to get it as dry as possible.
• Feta cheese: 6 ounces, crumbled. Choose a block-style feta brine-packed if you want superior texture—drain well and pat dry.
• Cheddar cheese: 8 ounces, shredded. A sharp or extra-sharp cheddar gives more savory depth; pre-shredded is convenient but freshly shredded melts more smoothly.
• Extra virgin olive oil: 1 tablespoon. Use a fruity, medium-intensity oil for sautéing; it adds subtle flavor without overpowering.
• Milk: 1/2 cup. Whole milk gives the creamiest texture; 2% also works if you prefer a lighter custard.
• Salt and pepper: 1/4 teaspoon table salt and 1/4 teaspoon ground black pepper, measured as a starting point and adjusted to taste before baking.
• Large eggs: 5. Room-temperature eggs blend into a silkier custard and rise more evenly in the oven.

Instructions

Preheat and prepare the dish: Preheat the oven to 350°F. Lightly grease a 9-inch (23 cm) deep-dish pie plate with a little olive oil or nonstick spray, ensuring the sides are well coated so slices release easily after baking. Cook the vegetables: Heat 1 tablespoon extra virgin olive oil in a large skillet over medium-high heat. Add the finely diced onion and sliced mushrooms and sauté until softened and lightly caramelized, about 5–7 minutes. Stir occasionally—look for translucency in the onion and golden edges on the mushrooms. Add the minced garlic during the last minute to avoid burning. Combine spinach and cheeses: Remove the skillet from heat and fold in the thoroughly drained spinach, 6 ounces crumbled feta, and 8 ounces shredded cheddar. Toss to distribute evenly; the residual heat will soften the cheeses slightly and help them nestle into the vegetable mixture. Transfer to pie plate: Spoon the vegetable and cheese mixture into the greased pie plate, pressing to create an even layer across the bottom and up the sides slightly so the custard will bake evenly. Whisk the egg base: In a mixing bowl, whisk together 5 large eggs, 1/2 cup milk, 1/4 teaspoon salt, and 1/4 teaspoon ground black pepper until the mixture is homogeneous and slightly frothy. Room-temperature eggs blend more smoothly, which helps the final texture. Assemble and bake: Pour the egg mixture evenly over the filling in the pie plate. Gently jiggle the plate so the liquid settles into any gaps. Bake in the preheated oven for 40–45 minutes, or until the eggs are set and the top is lightly golden—insert a knife near the center; it should come out clean with a slight moisture but not liquid. Rest and slice: Allow the quiche to cool for 10 minutes before slicing—this rest period helps the custard finish setting and makes cleaner slices. Serve warm or at room temperature.

Storage Tips

Store leftover slices in an airtight container in the refrigerator for up to 4 days. For longer storage, freeze individual slices wrapped tightly in plastic wrap and then foil; transfer to a freezer-safe bag for up to 3 months. Reheat from frozen at 325°F until warmed through, or thaw overnight in the fridge and reheat gently in a 350°F oven for best texture. Avoid microwaving from frozen if you care about keeping the custard's smooth texture—low, steady oven heat produces the best result.

Ingredient Substitutions

If you don't have feta, try goat cheese for a similar tang and creamy melting quality; reduce the amount slightly if it’s very soft. Swap cheddar for Gruyère or Swiss for a nuttier, more caramelized flavor. Use fresh spinach if preferred—sauté a generous 8 ounces fresh spinach until wilted and squeeze out moisture (roughly doubles the cooked weight compared to frozen). For dairy-free eaters, use a firm tofu-silk blend and a dairy-free shredded cheese alternative, but expect a change in texture and flavor.

Serving Suggestions

Serve slices with a peppery arugula salad tossed with lemon vinaigrette, roasted cherry tomatoes, or a simple mixed green salad for contrast. For a brunch buffet, pair with crusty gluten-free bread, fresh fruit, and a selection of spreads. Garnish with a sprinkle of extra crumbled feta, chopped fresh chives, or a light drizzle of good olive oil for an elevated presentation.

Cultural Background

Quiche in its crusted form is a classic from French country cooking, originally from the Lorraine region. This crustless adaptation is a modern, practical take that retains the custardy interior and savory fillings while removing the pastry component—popular among home cooks seeking gluten-free or lower-carb options. The use of spinach and cheeses reflects a Mediterranean influence, where greens and brined cheeses are common pairings.

Seasonal Adaptations

Spring and summer: swap mushrooms for blanched asparagus tips and add fresh herbs like dill or tarragon. Fall and winter: fold in caramelized leeks and roasted butternut squash cubes for a heartier profile. Holiday twist: add a pinch of nutmeg to the egg mixture and top with toasted walnuts for a warm, festive note.

Meal Prep Tips

Make the vegetable and cheese filling up to two days ahead and keep it refrigerated. Whisk the eggs and milk just before assembly to prevent separation. For easy portioning, bake in a 9-inch springform pan so you can remove the sides cleanly—this is especially useful if you plan to present the tart at a buffet. Pack slices in a shallow, leakproof container with a paper towel to absorb excess moisture for transport.

Whether you’re feeding a weekend crowd or making lunches for the week, this crustless spinach quiche is simple, reliable, and full of flavor. Give it a try with the cheese and herb combinations you love, and don’t be surprised if it becomes a household favorite.