Cook1 hr 10 mins
this is AMAZING!!!! Have some nice crusty bread to sop up the luscious juices. I served this as a main dish--serves 4 as a main dish, six-eight as a side. Please be sure to let this set out before serving, as the recipe instructs--it makes it a much more cohesive gratin.
FOR THE ONIONS
- 2 tablespoons olive oil
- 2 medium onions, thinly sliced
- 2 garlic cloves, minced
TO ASSEMBLE THE GRATIN
- 1 1⁄4 lbs ripe tomatoes, cored and cut into 1/4 inch slices
- 3⁄4 lb zucchini or 3⁄4 lb other green summer squash, cut into 1/4 inch slices on the bias
- 3⁄4 lb summer squash or 3⁄4 lb golden zucchini, cut into 1/4 inch slices on the bias
- 3 tablespoons olive oil
- 1⁄4 cup fresh thyme leave
- 1 teaspoon coarse salt
- 1 1⁄4 cups freshly grated parmigiano-reggiano cheese (I was out of this!!! So I just used freshly grated mozzarella.)
- fresh ground black pepper
- To cook the onions: In a medium skillet, heat the olive oil over medium heat.
- Add the onions and sauté, stirring frequently, until limp and golden brown, about 20 minute Reduce the heat to medium-low if they're browning too quickly.
- Add the garlic and sauté until soft and fragrant, 1 to 2 minutes.
- Spread the onions and garlic evenly in the bottom of an oiled 2-quart shallow gratin dish (preferably oval).
- Let cool.
- To assemble the gratin: Heat the oven to 375°F.
- Put the tomato slices on a shallow plate to drain for a few minutes and then discard the collected juices.
- In a medium bowl, toss the zucchini and squash slices with 1-1/2 Tbsp of the olive oil, 2 Tbsp of the thyme, and 1/2 teaspoons of the salt.
- Reserve half of the cheese for the top of the gratin.
- Sprinkle 1 Tbsp of the thyme over the onions in the gratin.
- Starting at one end of the baking dish, lay a row of slightly overlapping tomato slices across the width of the dish and sprinkle with a little of the cheese.
- Next, lay a row of zucchini, overlapping the tomatoes by two-thirds, and sprinkle with cheese.
- Repeat with a row of squash, and then repeat rows, sprinkling each with cheese, until the gratin is full.
- Season lightly with pepper and the remaining 1/2 tsp salt.
- Drizzle the remaining 1-1/2 Tbsp olive oil over all.
- Combine the reserved cheese with the remaining 1 Tbsp thyme and sprinkle this over the whole gratin.
- Cook until well-browned all over and the juices have bubbled for a while and reduced considerably, 65 to 70 minutes.
- Let cool for at least 15 minutes before serving.