Step 1

Preheat oven to 375°F and brush the bottom of a 9x12-baking dish with olive oil.

Step 2

Set the sliced squash on a kitchen towel to drain some of the excess moisture while you prep everything else.

Step 3

In a large bowl, toss the zucchini and onions with the pesto.

Step 4

Layer the baking dish with the marinara sauce, followed by the zucchini mixture. Spread the zucchini into one even layer.

Step 5

Sprinkle the top with the panko, Parmesan, a drizzle of olive oil, and pinches of red pepper flakes. Bake until the zucchini is tender (but not mushy) and the top is crispy and lightly browned - about 25 minutes. I like to turn my broiler on for the last few minutes to help the topping become browned and crisp.

Step 6

Remove from oven and let it cool 20 minutes before slicing.