Summer squash is composed mostly of water, which is really important to remember when building a casserole (otherwise known as a gratin) around this healthy and beautiful vegetable.

Too many times my summer squash casseroles are watery and flavorless. I decided to take on this challenge and see if I couldn't correct this issue. Thanks to the folks at America's Test Kitchen, I found the secrets to a non-watery and flavor-packed summer squash casserole!

First, they figured out how to remove the excess water from zucchini and summer squash and keep the crumb topping nice and crisp. They tossed 3 pounds of sliced squash with 2 teaspoons of salt and zapped the vegetable in the microwave. 8 minutes drew out excess water without destroying the squash.

The test kitchen pros explain why this works: "Salt draws out moisture by osmosis, but the water needs time to cross many cell walls. Microwaving breaks down cell walls. Since the water runs into fewer barriers, it comes out faster."

After they removed the squash from the microwave, they drained the slices and pressed them dry. Then they started combining ingredients. Good squash casseroles seem to have one thing in common: bread crumbs. But a bread-crumb-secret? You want them extra crispy to start with so they have a chance of staying crispy during and after baking. So the Test Kitchen cooks opted for extra-crispy Panko crumbs tossed with grated Parmesan cheese.

And here's the next big secret: I also learned from the Test Kitchen cooks that instead of just topping the casserole with crumbs, it's important to employ them throughout: crumbs layered on the bottom, in the middle layer, as well as on the top absorb moisture released by the baking squash.

Another important secret these cooks shared was that after the casserole bakes (covered), for 15 minutes, you add a final top layer of crumbs, which browns, but doesn't soak into the dish, and then bake for a final 15 minutes.

The final secret these cooks shared: You want to layer the squash slices with nicely caramelized onions and garlic, thyme, kalamata olives, and fresh basil. The conclusion? "Combined, these assertive seasonings proved perfect foils for relatively bland summer squash!" reports the Test Kitchen pros.

Filled with confidence and hope, I tried their suggestions and dared to serve yet another squash casserole at a family dinner last week. I was rewarded for my effort by oohs and aahs as they polished off two 9x13s of this super recipe. Many thanks to America's Test Kitchen cooks for sharing their secrets. Now if you want to make a non-watery squash casserole yourself, here's their delicious recipe: