This Keto Overnight Breakfast Casserole has become my go-to morning solution for busy weekdays and lazy weekend brunches alike. I first landed on this combination the winter I was juggling early meetings and a weekend baking habit; I wanted something I could prep the night before that felt hearty, tasted fresh, and stayed well within my low-carb goals. The texture is custardy from the eggs and heavy cream, studded with tender broccoli and melty cheddar, and punctuated by crisp bacon for a smoky finish. Every time I serve it, people are surprised that something so simple can feel so comforting.

I remember making this for a holiday morning when the house filled with the scent of baking eggs and melting cheese—the kind of aroma that pulls everyone out of bed. The casserole slices hold together nicely but remain soft in the center, which makes it ideal for reheating or packing for a portable breakfast. It’s forgiving, fast to assemble (about ten minutes), and bakes in under twenty minutes, which makes it a rare combination of speed, flavor, and low-carb nutrition.

Ingredients

• Frozen broccoli (1 12-oz bag): Use a steamable bag for convenience—I like florets that are uniformly sized so they heat through evenly. Frozen broccoli gives reliable texture and locks in color; if you prefer, thaw and pat dry to remove excess moisture.
• Shredded mild cheddar (1 cup): Choose a freshly shredded block cheddar if you can; pre-shredded often contains anti-caking agents that affect melt. Mild cheddar melts smoothly and complements the eggs without overpowering.
• Bacon (6 slices): Thick-cut or regular both work—cook until crisp for the best textural contrast. Reserve a small amount of bacon fat for flavor, or drain for a leaner version.
• Large eggs (4): Room temperature eggs will yield a more even custard; beat them well to incorporate air for a light set.
• Heavy cream (1/3 cup): Adds richness and creates a tender, custardy interior—half-and-half can be used in a pinch but will produce a slightly firmer set.
• Onion powder (1/2 teaspoon) & garlic powder (1/2 teaspoon): These dried seasonings distribute savory flavor throughout without adding moisture.
• Salt (1/4 teaspoon) & black pepper (1/4 teaspoon): Simple seasoning to brighten the eggs; adjust to taste, especially if your bacon is very salty.

Instructions

Prepare the broccoli and bacon: Heat the steamable bag according to package instructions or microwave the florets until just tender (about 3-4 minutes). Meanwhile, cook the bacon in a skillet over medium heat until crisp, about 8-10 minutes, turning once. Drain bacon on paper towels and chop into bite-sized pieces. Leave a teaspoon of rendered fat in the pan if you want an extra flavor boost—otherwise discard. Ensure the broccoli is well drained so the custard doesn’t become watery. Mix the custard: In a large bowl, whisk the 4 large eggs until homogenous and lightly frothy, about 30 seconds. Add 1/3 cup heavy cream, 1/2 teaspoon onion powder, 1/2 teaspoon garlic powder, 1/4 teaspoon salt, and 1/4 teaspoon black pepper. Whisk again until fully combined and slightly frothy; the whisked air will help create a tender texture when baked. Assemble in the dish: Preheat the oven to 375°F (190°C). Lightly grease an 8x8-inch baking dish or similar casserole dish. Spread the drained broccoli across the bottom in an even layer, sprinkle the chopped bacon evenly, and top with 1 cup shredded mild cheddar. Pour the egg-cream mixture over the top, pressing gently so the eggs distribute between the vegetables and cheese. Give the dish a gentle shake to settle the mixture. If the cheese appears sparse on top, add a few extra pinches for a golden finish. Bake until set: Place the dish in the middle rack and bake for 16-20 minutes, checking at 16 minutes. You're looking for the center to be set but slightly jiggly—an instant-read thermometer should read 165°F (74°C) in the center. Avoid overbaking to keep the interior custardy rather than rubbery. Let it rest 3-5 minutes before slicing. Slice and serve: Run a knife around the edge to loosen, then slice into 6 pieces. Serve warm with a sprinkle of fresh chives or a light drizzle of hot sauce if desired. Leftovers reheat well in the microwave for about 60-90 seconds depending on your appliance.

Storage Tips

To maintain the best texture, cool the casserole completely before refrigerating. Store in an airtight container or cover the baking dish tightly with plastic wrap for up to 4 days. For freezing, cut into serving portions, wrap each slice in parchment and then aluminum foil, and place in a freezer-safe bag for up to three months. Thaw overnight in the refrigerator and reheat in a 325°F oven for 10-15 minutes or microwave on medium power until warmed through. Avoid refreezing once thawed to preserve flavor and texture.

Ingredient Substitutions

If you don't have heavy cream, you can use half-and-half for a slightly lighter set—expect a firmer interior. Swap cheddar for Monterey Jack or Gruyère for a nuttier profile; both melt well. For a vegetarian version, omit bacon and add sautéed mushrooms or sun-dried tomatoes for umami. Use precooked sausage crumbles in place of bacon for a heartier, spicier option. If you prefer more greens, stir in spinach (squeezed dry) but reduce broccoli to prevent excess moisture.

Serving Suggestions

Serve slices with a bright side like a simple mixed-green salad dressed in lemon vinaigrette to cut the richness. For brunch, pair with sliced avocado, cherry tomatoes, or a dollop of sour cream flavored with chopped chives. It also works as a protein-rich lunch alongside roasted vegetables, or slice thinly for breakfast sliders on low-carb English muffins. Garnish with fresh herbs—parsley, chives, or dill brighten every bite.

Cultural Background

Baked egg dishes appear in many cuisines—think of crustless quiches in French cooking or strata variations in American brunch culture. This casserole draws from those traditions but simplifies them for low-carb living by removing any bread or pastry crusts and leaning into fatty, satisfying ingredients like cream and cheese. The practice of assembling ahead and baking later is a longstanding brunch technique favored for both convenience and flavor development.

Seasonal Adaptations

In spring, swap broccoli for asparagus tips and add fresh peas for color. In fall, use roasted butternut squash in small amounts (watch carbs) and swap cheddar for smoked gouda for a seasonal twist. Holiday versions can include chopped ham and sautéed leeks for celebratory mornings. Texture and moisture content change with substitutions, so adjust cream slightly to keep the custard just set.

Meal Prep Tips

Assemble this the night before in a disposable or oven-safe dish for a grab-and-go morning. Line the dish with parchment for easy removal if you plan to package slices. Portion into individual containers for weekday breakfasts and include a fresh herb packet and a small container of sliced avocado to finish after reheating. For bulk meal prep, double the recipe and bake in a 9x13-inch dish, increasing bake time by 8-12 minutes.

Bringing this all together, this casserole combines convenience and comfort without overcomplication. It’s an easy, adaptable way to ensure a satisfying low-carb start to the day and a reliable favorite to share with friends and family—try it once, and it’ll likely become a staple in your rotation.