Preheat the oven to 350 degrees F/180 degrees C

Fill a large bowl with cool water. Soak the squash for 10-20 minutes.

While the squash soaks, peel and chop the onion and garlic. Set a large saute pan out. One tablespoon of butter will be melted in this pan shortly. Use the other tablespoon of butter to grease the gratin dish.

Dry the squash well. Leave the peel on if you’re confident it isn’t covered in pesticides. Otherwise, peel it. Shred or finely slice the squash using a food processor with a grating attachment, a handheld box grater, or a large knife.

Place a colander in the sink. Toss the shredded/sliced squash in the colander. Mix 1 teaspoon salt with your clean hands, and allow the squash to drain for 10-20 minutes.

While the squash drains, melt the butter in the saute pan. Over medium heat, brown the onion and garlic. You want to add color and flavor. This should take about 8 minutes. You aren’t looking to cook the alliums to a deep mahogany brown.

Once the alliums take color, tip them into the gratin dish, spreading them evenly across the pan.

Fold the squash into a clean, non-linting dishcloth and squeeze as much liquid out as you can. Make sure your dishtowel is intact; mine had holes, and made a big mess.

Now brown the summer squash. There is no need to clean the pan. You may need to brown in relays, but rest assured the squash will cook down. As it browns, add it to the gratin dish, spreading it out evenly. I did not need to add more butter to my pan, but if you do, feel free.

Once all the squash has been browned and added to the gratin pan, add the seasonings, being sure to scatter as evenly as possible across the pan.

As noted in the post, you can drizzle olive oil over the gratin at this point and bake it. Or you can add the final ingredients.

Scatter the cheese and panko over the gratin. Pour in the dairy. It should come almost to the top of the gratin. Place the gratin dish on a baking sheet and slide it into the oven. Bake for about 40 minutes, or until the dish is browned, bubbling, looks and smells done. Not sure? Remove the gratin from the oven, place it on a wooden board, and take a tiny taste.

Serve summer squash gratin as a main course with salad and bread, or alongside poultry, pork, or as part of a vegetarian spread.

Leftover summer squash gratin will keep, covered and refrigerated, up to four days. To freeze summer squash gratin, place in freezer-safe dish or dishes. Wrap it in plastic wrap, then cover tightly with tinfoil and freeze, unbaked, up to three months. When you wish to eat the gratin, transfer baking dish or dishes directly from the freezer to the oven and bake.

Finally, as noted above, leftover gratin makes a terrific sandwich, with or without tomato. Try it with good white bread and a smear of Kewpie mayo.

Notes

Summer squash gratin is best prepared by what the French call au pif--by the nose. Meaning it is difficult to offer exact measurements. Only you know what type of squash you’re using, and how large they are. Only you can decide how much cheese your gratin requires, or how much panko is best. Treat my recipe as a blueprint. That’s all it really is.

Instead of the heavy cream used in the original recipe–that’s double cream to our British friends–I used half-and-half–which is half milk and half cream. You are welcome to substitute another dairy product, broth, or nut milk.

If you want to use a different cheese, aim for a cheese that complements the squash without overwhelming it. Squash is delicious, but it is bland. Cheddar gives the gratin a necessary lift. So keep that in mind.

My husband is not fond of onion. I used a small onion from the farmer’s market. Use whatever you like: scallion, shallot, white onions. All will work, in much larger quantities.

Alter the seasoning as you wish, but season carefully. Take care when using fresh thyme, as it can take over.

In memory of Carla Tomasi, the vegetable whisperer