Cheesy Zucchini Casserole (Creamy, Not Watery)

Cheesy zucchini casserole has a reputation for turning watery, and this recipe is built to prevent that. The slices are salted and drained first, then folded into a sour cream and cheddar sauce and topped with buttered panko and parmesan. The result is creamy and spoonable, not soupy. It serves 6, takes 60 minutes in total, and uses 2 lb of ordinary grocery-store zucchini, so you can make it any week of the year. It is also a dish that travels, which makes it a good Thanksgiving side, a potluck dish or the tray you take to a neighbor.

Why this works

• Salting and pressing removes about a third of the water in the slices before they ever meet the sauce.
• Sour cream, cheddar, onion and garlic make a sauce that coats every slice.
• Panko tossed with melted butter and parmesan bakes into a crisp lid.
• A 10 minute rest lets the sauce set enough to hold a spoonful.

Watery casserole is the main complaint with zucchini bakes, and the fix is mechanical, not magical. Water leaves the slices before they go into the dish, so there is less of it to dilute the sauce while it bakes. What is left is a thick, creamy coating that clings to each slice and holds together when you scoop it. The crumb topping is there for contrast, giving crunch on top of a soft center.

What to know about the ingredients

You need 2 lb of zucchini, 4 to 5 medium, sliced 1/4 inch thick. Slice them evenly so they cook at the same rate. The sauce is 1/2 cup sour cream with 1 1/2 cups of shredded cheddar, split between the sauce and the top, plus 1/2 cup of small-diced onion and 2 cloves of minced garlic.

For the topping you need 3/4 cup of panko, 1/4 cup of grated parmesan and 2 tablespoons of melted butter. Shred your own cheddar if you can. It melts more smoothly than the pre-shredded kind.

Slice the zucchini as evenly as you can, since thick and thin slices cook at different speeds. A mandoline helps if you own one, but a sharp knife and a steady hand are enough. Use full-fat sour cream, which holds up better in the oven than lighter versions. The onion is diced small so it softens through in the bake and does not stay crunchy, and the garlic is minced fine for the same reason.

Cheesy Zucchini Casserole

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The slices are salted and drained first, so the dish comes out creamy and not watery.

Prep25 min

Cook35 min

Total1 hr

Serves6

Scale1x2x3x

Ingredients

• zucchini, sliced 1/4 inch thick — 2 lb (4 to 5 medium) (900 g)
• cheddar, shredded — 1½ cups (170 g)
• sour cream — ½ cup (120 g)
• panko breadcrumbs — ¾ cup (45 g)
• parmesan, grated — ¼ cup (25 g)
• onion, diced small — ½ cup (80 g)
• butter, melted — 2 tablespoons (30 g)
• garlic, minced — 2 cloves (6 g)
• salt — 1 teaspoon (6 g)
• black pepper — ½ teaspoon (1 g)

Instructions

1. Toss the zucchini slices with 4 g (3/4 teaspoon) of the salt in a colander and let them drain 15 minutes. Press them between two clean towels until the towels come away damp, not soaked.
2. Heat the oven to 375 F (190 C) and butter a 9 by 13 inch (23 by 33 cm) baking dish.
3. Stir the sour cream, garlic, onion, the remaining 2 g (1/4 teaspoon) salt, pepper, and 115 g (1 cup) of the cheddar in a large bowl. This is the sauce.
4. Fold the drained slices into the sauce until every slice is coated, then spread the mixture in the dish in an even layer.
5. Toss the panko, parmesan, and melted butter in a small bowl until the crumbs look damp and hold together when pinched. This is the crumb topping.
6. Scatter the remaining 55 g (1/2 cup) cheddar over the casserole, then the crumb topping.
7. Bake 30 to 35 minutes, until the topping is deep golden and the edges bubble steadily around the whole rim.
8. Rest 10 minutes before serving so the sauce sets enough to hold a spoonful.

Nutrition per serving

271Calories

12 gProtein

13 gCarbs

19 gFat

Estimated per serving from standard nutrition reference values; will vary with brands and substitutions.

Tips for getting it right

1. Toss the slices with 4 g (3/4 teaspoon) of the salt and drain them 15 minutes. Do not skip this step.
2. Press the slices between two clean towels until the towels come away damp, not soaked.
3. Fold the drained slices into the sauce until every slice is coated, then spread them in an even layer in a buttered 9 by 13 inch (23 by 33 cm) dish.
4. Toss the crumb topping until it looks damp and holds together when pinched.
5. Bake at 375 F (190 C) for 30 to 35 minutes, until the topping is deep golden and the edges bubble all the way around.
6. Rest it 10 minutes before serving.

Taste the sauce before you fold in the slices. It should be pleasantly salty, because the zucchini will mellow it as it bakes. Spread the mixture to the corners of the dish so the edges do not dry out, and keep the topping even from side to side. If the top is browning faster than the edges are bubbling, tent the dish loosely with foil for the remaining time. Resist the urge to skip the rest at the end, since a spoonful served too early will run across the plate.

How to store, freeze and make ahead

Refrigerate leftovers for 4 days. You can assemble the casserole up to a day ahead, as long as you leave off the crumb topping and add it just before baking. This is not a freezer dish, because the slices go grainy once thawed. It also rests well, holding for 20 minutes before serving.

What to serve with it

Bring it to the table as a Thanksgiving side, a potluck dish or a tray for a neighbor. For a weeknight dinner, pair it with roast chicken or a simple green salad. A similar creamy side, Parmesan Zucchini Gratin, makes a good second dish on a holiday table.

Variations

• Stir a little chopped fresh herb into the sauce.
• Swap part of the cheddar for another melting cheese you like.
• Add a pinch of smoked paprika to the crumb topping.
• For a different comfort-food take with the same vegetable, try Sneaky Mac and Cheese or a tray of Sheet Pan Ratatouille.

For more zucchini ideas that work in every season, see Zucchini Recipes and Small-Batch Preserving.