Monday, 30 June 2014 | 37 comments

Herbed squash gratin

Sometimes life gives you lemons. Sometimes life gives you a behemoth summer squash on your doorstep.

Common wisdom holds that zucchini, yellow squash, and variants therein aren’t really good for much when they get this big. And to be fair, overblown summer squash are a little difficult to love. Spongy and squeaky when you cut into them and lacking the near-seedless-ness that makes smaller, sweeter squash so amenable, most people—Nigel Slater included—advise scooping out the innards and stuffing them. Poor, big ol’ summer squash: relegated to the role of an edible casserole dish.

I set out to use the squash in a non-stuffed way that still made it interesting and good. Typically I make this herbed squash gratin with smaller zucchini, but thinly slicing the larger squash worked perfectly, and the dish cooks long enough that there’s no need to remove the starting-to-be-tough skin. Salting and draining the water from the squash is definitely required no matter the size of squash you employ for this recipe—if you skip that part, your gratin will be swimming in zucchini water that tastes like bad vegetable broth.

We eat this for a light summer dinner or as a side for a heartier affair. While I’ve adapted this recipe from several outlets that bill it for summer squash only, I think it lends itself perfectly for winter squash, too. The recipe below is presented as a “template recipe”: guidance on how to make this no matter what you have around, no matter the time of year. This is a key to seasonal cooking, I think, and I hope to start collecting more of these types of recipes here.

Herbed squash gratin

You’ll need

  1. For the herb sauce—
  2. 1 ½ cups coarsely chopped mixed green seasonal herbs: parsley, mint, basil, marjoram are all good spring/summer choices; or oregano, rosemary, sage for fall/winter
  3. ¾ cup olive oil (or oil of choice)
  4. 1 small clove garlic
  5. Several tablespoons vinegar of choice (I like sherry vinegar here) or fresh lemon juice
  6. Freshly ground black pepper
  7. For the squash—
  8. 2 pounds squash
  9. 1 ½ cups fresh coarse bread crumbs (Panko works too)
  10. 3 tablespoons unsalted butter
  11. ¾ cups thinly sliced onion
  12. 1 teaspoon minced garlic
  13. A few pinches chile flakes, if desired
  14. 1 cup grated hard salty cheese, such as Parmigiano or Gruyere or Cheddar
  15. Kosher salt and freshly ground black pepper


  1. Make the herb sauce. In a food processor or mortar and pestle, coarsely pulverize the herbs. Pound the garlic and add it to the mixture. Stir in olive oil, vinegar/lemon juice, and a pinch of black pepper. Taste for seasoning and adjust.
  2. Heat the oven to 400 degrees Fahrenheit. If using summer squash, slice into 1/8-inch thick slices. Toss the slices in a bowl with a few hefty pinches of kosher salt. If using winter squash, halve, peel, seed, and then slice into 1/8 inch slices. Season lightly with salt.
  3. Melt the butter in a skillet until foams up, subsides, and begins to brown. Toss the breadcrumbs in a bowl with the butter.
  4. Discard any accumulated liquid in the bottom of the bowl with the squash in it. To the squash, add the onions, minced garlic, chile (if using), ½ cup herb sauce, and and some pepper. Toss, and add the cheese and half the breadcrumbs. Toss again and taste for seasoning (the raw garlic will be strong at this point, but will mellow in cooking).
  5. Place mixture in a 9-inch casserole dish or in a skillet. Top with remaining breadcrumbs. Bake for 35-40 minutes for summer squash and up to an hour for winter squash, until the squash is tender and the top is dark golden

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§ 37 responses to Herbed squash gratin

  • Whoa, herb cubes! That’s an amazing idea. Last year, I had an overgrown basil plant and a lot of it went to waste when the winter months came around. How long do herb cubes usually last in the freezer?

    • A long time—the basil in this photo is from last July! For basil I just make full-on pesto (very thick). Freeze in ice cube trays, pop out, store in freezer bags. It’s not the same as fresh herbs, obviously, but it something that is cooked, they retain a lot of flavor. Pro-tip: a squeeze of lemon juice keeps the color from getting a bit murky. Also shown here are lemon balm paste and wild onion paste (just herbs, oil, salt, blitzed in a food processor).

      • Bless the longevity powers of freezing, hah.. Thanks for the tips. I actually just made a bunch of pesto. Now I know what to do with any of the excess!

  • Love the photo of the long squash on the scale. Hilarious. I had to buy an absurd quantity of thai basil this weekend, so perhaps I will freeze with some lemon juice per these instructions.

  • This gratin looks so yummy! Love the topping!

  • Maggie

    I love squash prepared this way. I made a similar dish not too long ago — yours is truly a ribbon winner in the veg category!

  • fabulous! I love your herb packages! so smart! There are always a few zucchinis that I don’t see until they’re the size of baseball bats. Great idea!

  • I actually never knew about gratin until I encountered in Japan, oddly enough. I still have yet to actually try it, since I don’t eat dairy that much. Is gruyere cheese commonly used in gratin? Is gruyere cheese hard and dry like a block of Parmesan cheese is?
    Thanks for posting,

  • Yum!

  • Margit Van Schaick

    Love to gather recipes like this that are nutritious, frugal, and delicious to eat. Using every bit of a productive garden is one of the main ways I use in trying to make ends meet. And, it’s fun for me to be creative and adventurous in the kitchen. Thank you. I look forward to the future recipes you mention. BTW, Margaret Roach in her blog, “A Way To Garden”, has some wonderful tips for freezing herbs and produce from her garden–being vegetarian, she is a wonderful resource not only for growing a garden, but also concerning eating delicious food from it.

  • I’m tucking this away for a few weeks from now when my squash plants start to really go crazy. Sounds wonderful!

  • I’m a huge gratin fan, and I love that you didn’t drown your squash in cream and cheese for this one. It looks great.

  • I just wanted to say I totally agree that “templates” or “sketches” of recipes are the key to eating seasonally and with what you can find in your area. Realizing that recipes are flexible, and not getting stuck on having any one specific thing is so empowering. Thanks for the ideas!

  • This looks perfect. I love that it is more of a template recipe because there really is so much you can do with it depending on what is in-season and what you have around. And I will definitely need to make some frozen herb cubes too!

  • Susan

    Made this for dinner last night, and oh my goodness was it delicious! Thank you very much!

    Any good suggestions for what to do with the kohlrabi the CSA is currently bombarding me with?

    • Honestly, you could treat the kohlrabi similarly to this if you wanted. Probably a longer baking time, though. Chilled kohlrabi soup is nice, too. –S

      • Susan

        Chilled kohlrabi soup?!?! Tell me more?

        • I basically just follow the same template I would for any chilled blended soup: slowly saute chopped yellow onion in butter, add kohlrabi, saute a few more minutes, add stock or broth, season, cook until very tender, then blend carefully in a blender in batches or with a hand/immersion blender. Would be really nice with dill, now that I think about it.

  • I just stumbled across your site and, in one day, I have read every. single. post. Your writing is breathtaking and your simple (in a good way) and improvisational approach to cooking, of which this gratin is but one example, is an inspiration. I’ll be back again!

  • I suppose this would work well with yellow zucchinis from our garden. looks lovely.

  • heidi defaut

    i love squash! i have had good results with all kinds that are misshapen, too big, etc with using them for zucchini- for example-patties or pancakes because you can grate then or chop them up and they do a great job. also love this treatment. really enjoy your site, thank you.

  • Made this tonight. My fiance and I loved it! Looking forward to using the rest of that herb sauce tomorrow, too. Maybe in a sandwich?

  • This looks so great! I can’t wait for my squash to be ready so I can make this. Looks like a great dish to bring to a potluck too! I’ve got cilantro growing EVERYWHERE in my garden, I’m going to pick it and make your herb pops with it.

  • Wonderful recipe. However, you call for 3/4 cups of olive oil, then later we use 1/2 cup of the olive oil mixture. Is the remaining 1/4 cup supposed to be absorbed by the herbs? We probably didn’t use enough herbs, but with 3/4 cups olive oil it was swimming in old. Not sure where the other 1/4 cup was supposed to go.

  • meliSsa

    this is SO good. going to be making it regularly this summer. i loved making a big pan and having it around for a dinner side or work lunch all week. thanks for sharing!

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