Bake for 30 minutes. The zucchini should be beginning to soften, and the beef should be mostly cooked through. While it bakes, I usually clear the mail off the table, which is a ridiculous ritual in this house. Why does junk mail multiply faster than zucchini? Nobody knows.
Carefully remove the foil—it will release a blast of steam, so don’t lean right over it like I did and then complain about my glasses fogging up. Sprinkle the mozzarella evenly over the tops of the beef-filled zucchini.
Return the dish to the oven uncovered and bake for another 10 to 15 minutes, until the cheese is melted and lightly golden. Check the thickest part of the beef in one zucchini boat with an instant-read thermometer; it needs to reach at least 160°F. I know thermometers feel like one more thing, but ground beef is not where I choose to be casual.
Let the zucchini boats rest for 5 to 10 minutes before serving. They’re easier to lift out, and the juices settle down a bit. Spoon that warm sauce from the bottom of the dish over each serving. Extra Parmesan and crushed red pepper at the table are never a bad idea.
Variations
For little kids—or grown people with very firm opinions about green things—use a mild marinara and leave out the Italian seasoning. They can add their own cheese at the table, which somehow makes it more acceptable.
You can swap the mozzarella for an Italian cheese blend, or cheddar if that’s what you have. Cheddar is not traditional, exactly, but neither is a late dinner, and life goes on. If your zucchini are especially large, you may need a little extra sauce and cheese and a few extra minutes in the oven.
I have also finely chopped some of the scooped-out zucchini centers and gently mixed them into the ground beef. That works well. One time I tried adding a bunch of breadcrumbs, thinking I was being clever, and the filling got too bulky and oddly dry. So I don’t do that anymore. Clever is overrated. You might also like our Chocolate Zucchini Bread.
Storage & Reheating
Cool leftovers and get them into the refrigerator within two hours. They’ll keep well for 3 to 4 days in a covered container. The zucchini does soften more as it sits—there’s no getting around that—but the flavor is still good, maybe even better after resting.
Reheat individual portions in the microwave until steaming hot, or warm them covered in the oven if you have more time. Add a spoonful of marinara if the dish looks dry. Leftovers are good chopped up over egg noodles, which is not elegant but is honestly pretty smart. I prefer eating one cold from the fridge while deciding what to make for lunch.
Final Notes
There’s something comforting about a meal that doesn’t ask much of you. Especially when everybody is sticky and slightly irritable and the sun is still glaring through the kitchen window like it pays the mortgage.
These beef stuffed zucchini boats are not glamorous. They’re not meant to be. They’re just dependable: tender zucchini, savory beef, red sauce pooling around the edges, cheese stretching from fork to plate if you catch it at the right moment. Try our Greek Roasted Vegetables next.
And if someone at your table says they “don’t really like zucchini,” well… hand them one anyway. With enough mozzarella, most of us can be persuaded. If you like this, you’ll love our 3-Ingredient Slow Cooker Zucchini Dessert.

