Summer Squash Gratin with Salsa Verde and Gruyere

Salsa Verde

• 1 teaspoon fresh marjoram or oregano leaves (1/2 teaspoon dried)
• 1/4 cup coarsely chopped mint
• 1 cup coarsely chopped flat-leaf parsley
• 3/4 cups extra-virgin olive oil
• 1 small clove garlic
• 1 anchovy
• 1 tablespoon capers, drained (rinsed if salt-packed)
• 1/2 lemon, for juicing
• Freshly ground black pepper

Gratin

• 2 pounds summer squash
• 1 1/2 cup fresh breadcrumbs
• 3 tablespoons unsalted butter
• 3/4 cups sliced shallot
• 1 teaspoon minced garlic
• 1 tablespoon thyme leaves
• 1 New Mexico chile or jalapeno, seeded and finely chopped
• 1 cup grated Gruyere cheese
• Kosher salt and freshly ground black pepper

1. Make the salsa verde. Using a mortar and pestle (or a food processor, I won't tell anyone), pound the herbs to a paste. You may have to do this in batches. Work in some of the olive oil, and transfer the mixture to a bowl. Pound the garlic and anchovy, and add them to the herbs.
2. Gently pound the capers until they're partially crushed, and add them to the herbs. Stir in the remaining oil, a pinch of black pepper, and a squeeze of lemon juice. Taste for balance and seasoning.
3. Make the gratin. Heat the oven to 400 degrees. Cut the squash into 1/8-inch-thick slices. Toss the slices in a large bowl with 1 teaspoon kosher salt, and let sit 10 minutes.
4. Place the breadcrumbs in a bowl. Heat a small saute pan over medium heat for 1 minute. Swirl in the butter and cook for a few minutes, until it browns and smells nutty. Pour the brown butter over the breadcrumbs (being sure to scrape all the brown bits into the bowl with a rubber spatula). Wait a minute or so for the butter to cool, and toss well.
5. Drain the squash and transfer it to a large mixing bowl. Add the shallots, minced garlic, thyme, chile, 1/2 cup salsa verde, and some pepper. Toss to combine, and add the cheese and half the butter-coated breadcrumbs. Toss again, and taste for seasoning. (The raw garlic will taste strong at this point but will be delicious when cooked.)
6. Place the squash in a pretty 9-by-9-inch (or equivalent) gratin dish (I used a skillet). Scatter the remaining breadcrumbs over the top, and bake 35 to 40 minutes, until the squash is tender and the top is crisp.