Sourdough Broccoli Casserole

This sourdough broccoli casserole combines crisp-tender broccoli with a creamy, cheesy sourdough discard sauce and a buttery breadcrumb topping. Baked until golden and bubbling, it’s an easy side dish the whole family will love!

Course Side Dish

Cuisine American

Keyword Sourdough Discard

Prep Time 30

Cook Time 25

Servings Servings

Calories 450kcal

Author Kate Freebairn

Equipment

Large Saucepan
2-quart Baking Dish (about 9" x 9")

Ingredients

650 g Broccoli Florets (about two small heads)
60 g Butter (salted or unsalted)
100 g Sourdough Discard (can be active or discard)
400 g Whole Milk
200 g Chicken Stock or Broth
250 g Cheddar Cheese shredded
50 g Parmesan Cheese finely grated
5 g Salt (1 tsp- plus more for the blanching water)
2 g Garlic Powder (1 tsp)

Topping

50 g Sourdough Breadcrumbs
40 g Butter melted (or olive oil)
35 g Parmesan Cheese finely grated

Instructions

Preheat the oven to 200℃ / 400℉.
Bring a large pot of salted water to a boil. Add the broccoli florets and cook for 2 to 3 minutes, until bright green. Drain immediately and set aside.
Now add butter, sourdough starter and a dash of the milk into a saucepan and whisk over very low heat to form a roux. As it comes together and starts to cook, add a little more milk and continue whisking.
Continue whisking over medium heat as you add more of the milk, a little at a time, until all of the milk has been added. Cook, whisking frequently, for around 5 minutes and you'll see the white sauce begin to thicken. Slowly drizzle in the stock and continue whisking until the stock is fully incorporated.
Cook until the sauce is quite thick and coats the back of a spoon. Remove the sauce from the heat and add the shredded cheeses, salt and garlic powder. Continue whisking until all of the cheese has melted through (it really doesn't take long).
Add the broccoli on top of the cheese sauce and stir to coat thoroughly, then transfer the broccoli and cheese mixture into a 2-quart baking dish.
To make the topping, combine the breadcrumbs, parmesan and melted butter in a small bowl. Stir to combine and sprinkle on top of the broccoli and cheese mixture.
Bake for about 25 minutes, or until the topping is golden brown and the cheese is bubbling on the edges. If possible, let sit for 10 to 15 minutes before serving to let the sauce thicken up.

Notes

I recommend salting your blanching water well, and don’t overcook the broccoli! It only needs 2 to 3 minutes, and you want to strain the vegetables when they’re still bright green.
The broccoli will leach a little water as it bakes in the casserole, so cook your cheese sauce on the stovetop until it’s just a bit thicker than you want it. When it bakes with the broccoli it will thin out.
If you can, I also recommend allowing your sourdough broccoli casserole to sit for 10 to 15 minutes after you remove it from the oven to let the cheese sauce thicken further. It’s worth the wait!

Nutrition