Have you tried broccoli casserole? While it’s a familiar comfort dish in many Southern kitchens, versions of this creamy, baked vegetable dish appear in households across the country. Traditional broccoli casseroles are indulgent: cheese, canned cream soup, butter, and crunchy cracker toppings make them rich and deeply satisfying. But if you want the same cozy flavor without dairy, gluten, or grains, this Whole30 Broccoli Casserole offers a flavorful, health-conscious alternative that still feels like a holiday side or weeknight favorite.
This Whole30 take keeps what’s best about the classic—creamy sauce, tender broccoli, and a crunchy topping—while using simple, compliant ingredients. The sauce is built from butter or ghee and arrowroot for thickness, bolstered by mushrooms and vegetable broth for savory depth. A mayo-and-egg mixture binds the broccoli, while pecans add a toasted crunch in place of crackers. The result is a savory, satisfying casserole that’s dairy-free, gluten-free, and grain-free, and it serves well alongside roasted meats, as part of a holiday spread, or as a stand-alone vegetarian main.
- 6 cups broccoli, cut into small florets and roughly chopped
- 1/2 cup yellow onion, finely diced (about 1/4 medium onion)
- 1 cup Whole30-compliant mayonnaise (homemade or store-bought compliant mayo)
- 2 eggs, lightly whisked
- 1.5 tablespoons nutritional yeast (optional, for a savory, cheesy note)
- 2/3 cup pecans, loosely chopped for the topping
- 2 tablespoons butter or ghee
- 2 tablespoons arrowroot flour (or tapioca starch) to thicken
- 1/2 teaspoon paprika
- 1/4 teaspoon cayenne pepper (adjust to taste)
- 1/2 teaspoon garlic powder
- 1 teaspoon kosher salt
- 1/2 teaspoon black pepper
- 1.5 cups baby bella mushrooms, diced small (about 4–6 mushrooms)
- 1 cup low-sodium vegetable broth
- Preheat the oven to 350°F (175°C).
- Steam the broccoli: place florets in a steamer basket set over simmering water, cover, and steam for about 5 minutes until bright green and slightly tender but not mushy.
- While the broccoli steams, prepare the sauce (see next section).
- In a large bowl combine the steamed broccoli, diced onion, mayonnaise, whisked eggs, and nutritional yeast. Add the prepared sauce to the bowl and stir until everything is evenly coated.
- Transfer the mixture to a 9×11-inch baking dish and sprinkle the chopped pecans evenly across the top.
- Bake for 30–40 minutes, until the casserole is bubbling at the edges and the top is golden. Remove from oven and let rest for 10–15 minutes before serving to allow the sauce to set.
- In a small saucepan over medium heat, melt the butter or ghee.
- Whisk in the arrowroot flour, paprika, cayenne, garlic powder, salt, and pepper until smooth and fragrant.
- Stir in the diced mushrooms and the vegetable broth, combining thoroughly.
- Reduce the heat to medium-low and cook, stirring, until the sauce thickens slightly, about 1–2 minutes. Remove from heat and set aside until ready to mix with the broccoli.
This casserole adapts easily to your preferences. For a nuttier topping, substitute chopped almonds or walnuts for pecans. If you prefer more mushroom flavor, increase the mushrooms to 2 cups, or swap in shiitake for a deeper umami note. The nutritional yeast adds a cheese-like savor; omit it if you don’t have any, but the casserole will be slightly less savory.
For a lighter version, reduce the mayo to 3/4 cup and add an extra egg white to help bind. If you’re not following Whole30 and want a richer finish, a few tablespoons of grated hard cheese stirred into the broccoli mixture would work well.
Make-ahead and storage: Assemble the casserole up to the point of baking, cover, and refrigerate for up to 24 hours. Add the pecans just before baking to preserve their crunch. Leftovers will keep in an airtight container in the refrigerator for 3–4 days; reheat portions in the oven at 350°F until warmed through, or microwave individual servings.
Serving suggestions: This broccoli casserole pairs nicely with roasted chicken, glazed ham, or baked salmon. It also stands on its own as a hearty vegetarian main served with a simple green salad. For holiday meals, place it alongside mashed potatoes or a grain-free stuffing for a balanced plate.
Dietary notes: This recipe is designed to be dairy-free, gluten-free, and grain-free when made with compliant ingredients. Verify that your mayo and any packaged ingredients are labeled compliant if you are following a specific eating program.