Meanwhile, I've made Summer Squash, Potato & Tomato Gratin, with sausages and onions sandwiched between layers of potato and squash. The gratin uses just 1 cup of cheese and forgoes the custardy combo of heavy whipping cream and eggs, so it will be lighter in texture than most versions.
Using sausage in the gratin ramps up its flavor and enhances the potato, which is more neutral-tasting than the squash. You can adjust the flavors by using chicken sausage or even spicy Italian. You can also use precooked sausage cut into fine or medium dice. Vegetarians can substitute marinated tofu, legumes or more vegetables for the sausage layer.
SUMMER SQUASH, POTATO & TOMATO GRATIN
o Serves 4 to 6
The flavors in this dish will depend on the type of sausage you use. You can also assemble and partially bake this dish ahead. If refrigerated, bring the gratin to room temperature before baking it or allow additional time. Leftovers can be frozen.
1-1/2 teaspoons kosher salt plus more as needed
3/4 teaspoon black pepper
1-1/2 teaspoons chopped fresh or generous
1/3 teaspoon dried thyme, crumbled
1 pound russet potatoes, about 2 potatoes
3 ounces Gruyere, grated, about 1 cup
1/2 pound lean sausage, in bulk or removed from the casing
Large pinch smoked paprika, to taste
Large pinch cayenne pepper, to taste
1 teaspoon olive oil plus more, as needed
1 small yellow onion (about 8 ounces), very thinly sliced, about 1/2 cup
1 to 1-1/2 teaspoons minced garlic, about 2 cloves
1 to 1-1/4 pounds summer squash, such as pattypan
1 teaspoon chopped parsley (optional)
1/2 cup whole milk
1 pound tomatoes (see Note), about 2 large tomatoes
Preheat the oven to 400 degrees. Prepare an 8-inch square pan with a light coat of oil or pan spray; set aside. Combine 1-1/2 teaspoons kosher salt, pepper and thyme in a small dish; set aside.
Peel potatoes and cut into 1/8-inch-thick slices, using a mandolin if available, keeping them in water until ready to cook to prevent oxidation. Par-cook the potatoes in batches, either by blanching, steaming or microwaving, until they are translucent and fairly soft (but you should still be able to pick them up without breaking).
Layer the potatoes in the pan, slightly overlapping the slices; season each layer with some of the salt-thyme mixture. Sprinkle about 1/3 of the cheese over the final potato layer.
Combine sausage, paprika, cayenne and salt to taste in a skillet over medium heat (you may need to add a little oil if the sausage is extremely lean). Brown the sausage, breaking it into small pieces as it cooks. When done, transfer to a bowl.
Add onions to the same skillet, along with a little more olive oil, if needed. Cook, stirring occasionally, until onions soften and begin to caramelize, about 4 to 5 minutes. Add garlic and cook until aromatic, about 30 to 45 seconds. Add this to the sausage in the bowl, mix to combine, then spread over the potatoes. Top with another 1/3 of the cheese.
Cut the squash crosswise into 1/8-inch-thick slices, then par-cook similarly to the potatoes. Layer the squash over the onion-sausage mixture, sprinkling each layer with some of the salt-thyme mixture and parsley, if using. Pour milk over all, and season to taste.
Chop the tomatoes into 1/2-inch pieces, reserving any juices. Cover the squash with the tomatoes and juices and a final sprinkle of salt-thyme mixture.
Place a piece of parchment paper over the top of the dish; cover loosely with foil. If desired, place a baking sheet (optionally lined with parchment) under the pan to catch any drips. Bake until the vegetables are tender and easily pierced with a skewer, about 1 hour, depending how much the vegetables were par-cooked.
Remove dish from oven, remove foil and parchment; if needed, bake a bit longer to evaporate excess liquid, then sprinkle the remaining cheese over the tomatoes. Bake, uncovered, until cheese melts.
Straight out of the oven, it may seem that there is a lot of liquid in the pan, but much of it will be absorbed as the dish rests. Cool at least 15 minutes before serving.
Note: You can substitute 1-1/2 to 2 cups chopped canned tomatoes with juices.
Per serving: 241 calories, 12 g protein, 24 g carbohydrates, 11 g fat (5 g saturated), 33 mg cholesterol, 781 mg sodium, 4 g fiber.