This grilled zucchini and squash is the perfect side dish for summer nights with friends and family. It’s a simple recipe that tastes great and has endless options. Zucchini and yellow squash are paired with a marinade that comes together in a snap, then grilled until tender and slightly charred. Serve with fresh herbs, a squeeze of fresh lemon juice, or a little crumble of feta.
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I like to think of this recipe as the summer version of my favorite roasted squash and zucchini recipe.
It’s perfect for those dog days of summer when it’s so hot you can’t bear the thought of turning on the stove or oven.
📖Why This Recipe Works
This recipe, though very simple, is packed with tons of flavor. The marinade is perfectly balanced and complements the zucchini. We don't throw out the excess mariande but add the vegetables back in post-grilling to grab every bit of extra flavor.
But perhaps the most important issue when making grilled vegetables is what is the best shape. I tested three different shapes and several cooking temperatures and times to bring you the best result.
How to Cut Zucchini and Squash
This recipe calls for zucchini and yellow summer squash that has been sliced lengthwise into planks.
I tested three different shapes of zucchini – rounds, spears, and planks. The plank shape turned out to be the best for grilling because the shape allows them to be turned easily and doesn’t allow them to fall through the grill grates.
But let's talk about why rounds and spears were not the best way to cook these specific vegetables.
First, the rounds. Rounds easily fall through the grates so some type of grill pan is needed. They tend to easily overcook. You could cut them on the bias to make large oval shape slices but then we have a lot of waste with the ends.
For the spears, my biggest issue was the texture. The zucchini spears seem to cook faster than the squash. And the smaller pointed end of the spears got mushy while the spine with the skin wasn't tender enough.
For these reasons- you want to cut your vegetables into flat strips.
Zucchini and Yellow Squash - Choose medium-to-large zucchini and squash for best results. If you can only find one or the other, use what you’re able to get.
Olive Oil - Any high-quality oil will be fine, such as avocado or grapeseed oil.
Dijon Mustard - Mustard has a pungent bite that is delicious against the mild summer squash. Brown mustard or any type of grainy mustard will work but skip the yellow mustard.
Garlic - Use fresh garlic, not garlic powder for the best flavor, you will need one to two cloves.
Dried Thyme - Dried thyme has a lovely, earthy flavor that is amazing with the zucchini. You can use fresh thyme but I found it tended to burn during my recipe testing.
Crushed Red Pepper Flakes - This is optional but I like the little bit of heat.
See the recipe card for exact quantities.
💭 Seasoning Options
Switch up the marinade to your preference or just try something new - there are endless possibilities for this recipe.
Try out some of these combinations.
- Blackened: Use my homemade blackening seasoning and just add the olive oil for a spicy Cajun twist.
- Italian: Use an Italian seasoning blend in place of the thyme. Once grilled, top with some grated parmesan cheese and a side of san marzano sauce for dipping.
- Chimichurri: Swap out the marinade for my homemade chimichurri.
- Moroccan: Add harissa paste to the marinade in place of the mustard. Once grilled, top with chopped onions and tomatoes.
⏲️How to Make Grilled Zucchini and Squash
This light and fresh dish only require a few steps to transform the humble zucchini into a show-stopping side for your next outdoor dinner party or weeknight family meal.
Step 1: Slice the Zucchini
Trimming the ends off of the zucchini and the squash is optional. Cut them lengthwise into slices about ¼ to ½ inch thick. I find the
Step 2: Mix the Marinade
Add the olive oil, mustard, thyme, garlic, pepper flakes, salt, and pepper to a small bowl. Whisk to combine. Then, add the zucchini and squash slices to a mixing bowl and toss with the marinade.
It helps to use your hands to ensure all the pieces are fully coated with the oil. We don't want the vegetables sticking to the hot grates.
Allow the squash and zucchini to marinate while the grill preheats.
Step 3: Grill the Zucchini
Place the squash and zucchini slices onto a hot grill in a single layer. Shake off any excess marinade as you place them on. Grill the zucchini for 2-3 minutes per side. The vegetables should retain a bright color and have light grill marks.
It is important that you don’t close the lid of the grill. You need to allow the steam to escape, otherwise, you will get mushy veggies.
Step 4: Serve
When the squash is cooked, place them on a platter and top with any excess marinade. Top with fresh herbs or a sprinkle of cheese.
🥗What to Serve with Grilled Vegetables
In addition to herbs and cheese (I like feta or goat cheese). Try topping the zucchini with rich and flavorful homemade compound butter, this perfectly smooth and creamy avocado crema, or this incredibly flavorful and easy homemade romesco sauce. Check out more healthy sauce recipes for more ideas!
Grill up some juicy steak or these flavorful grilled chicken thighs. Pair them with the marinated summer squash, and this creamy blue cheese potato salad, light, and refreshing lemon orzo salad, or these Greek roasted potatoes for the ultimate summer meal.
👩🏻🍳 Expert Tips
- Don't use extra large zucchini. Those are better for shredding into zucchini bread or making zucchini soup.
- Be careful when slicing, an even thickness on the vegetable slices will ensure even cooking.
- When grilling the squash, place the slices perpendicular to the grill grates. This will keep them from falling through as well as give them some pretty grill marks.
Once the zucchini is cooked, they can be cooled down to room temperature before storing in an airtight container in the refrigerator for up to 4 days. Reheat in a pan on the stovetop or even in the microwave.
This recipe should be enjoyed shortly after preparation, and should not be frozen.
More Zucchini and Squash Recipes
💭 Frequently Asked Questions
While many recipes have you oil the grill grates, this recipe contains enough oil in the marinade to prevent sticking on well seasoned grates. If your grill is new, I recommend oiling them.
Once cooked, the zucchini is very soft. Without the skin, it can easily fall apart. For this recipe, it’s best to use unpeeled squash and zucchini.
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Grilled Zucchini and Yellow Squash
- Cut both zucchini and squash lengthwise into slices between ¼ and ½-inch thick.2 medium zucchini, 2 medium yellow squash
- Whisk together the remaining ingredients to make a marinade. In a large bowl, combine the sliced vegetables and marinade. Gently toss to combine. Let the vegetables marinade while the grill pre-heats, ideally about 15 minutes.¼ cup extra-virgin olive oil, 1 Tablespoon dijon mustard, 1 teaspoon garlic, 1 teaspoon dried thyme, ½ teaspoon kosher salt, ¼ teaspoon black pepper, ¼ teaspoon crushed red pepper flakes
- Pre-heat your gill to medium heat, which is 400-450 F degrees.
- Shake the excess mariande off as you place the zucchini and squash slices on the grill, they should be perpendicular to your grill grates, not parallel, to prevent the vegetables from slipping through the grates. Do not throw away the excess marinade. Grill for 2 to 3 minutes per side. Keep the lid of the grill open during cooking to prevent the vegetables from steaming.
- Remove the grilled vegetables to a platter drizzle over the excess marinade. Season with salt to taste, garnish with fresh herbs if desired.
- If using a grill pan allow it to preheat for 8 to 10 minutes.
- I recommend cutting into strips for the best result. You can also cut the squash and zucchini into rounds or spears. If using rounds you will need a grill basket. See the post for notes on cooking times and other key info.