Not pictured in the photo from our French barbecue was a zucchini gratin made by Stephanie’s mom, which I believe served as the only vegetable side that night. It was so very delicious that I felt compelled to ask Chris what she had put in it: « Just steamed zucchini, potato puree (from flakes!), milk, butter, and Gruyère on top. C’est tout », she said.
The memory of it stuck with me, and I made a mental note to attempt one myself after we got back from France. That sometime was last Monday, after returning from a visit to Petaluma with a plump zucchini from a friend’s garden. Along with some red potatoes that I’d been preserving in the fridge for far too long, and some pattypan squash from our veggie box two weeks prior, I had everything I needed, and set to peeling and steaming the lot. Once the veggies were suitably limp, I mashed them together with some butter only to discover I had made soup, not puree. No need for milk. I put the mixture into a pot to simmer in hopes that it might thicken.
Meanwhile, visions of hachis parmentier (aka shephard’s pie) danced in my head upon realizing that we had half a pound of uncased Italian sausage leftover from the pizzas we made while my parents were in town. Once I started the sausage browning, a long neglected onion also caught my eye. The center had gone bad, but the outside layers were still usable, so in it went.
What else could this “stone soup” gratin accommodate? We’ve been getting containers of little Japanese shishito peppers from our CSA every other week, which I decided to de-seed and chop while the sausage and onions browned. I tossed the peppers in to cook a little at the end. When all the meat and veg looked good and caramelized, I combined it with the somewhat thickened potato-zucchini-squash puree so the flavors would mingle (rather than remain segregated à la hachis parmentier).
Finally I grated the ends of two different types of cheese I found in the fridge: a mild raw milk cheddar and a pepper-crusted Toscano. I mixed a handful into the puree and put the rest on top. The gratin went into oven until Stephanie came home from work and declared the crust golden enough to eat. It was very very tasty. Thank you Chris for the inspiration!