Before the summer finishes, I want to share this amazing vegetable gratin dish with you. My interest in this recipe started as a way to get rid of my mountains of zucchini and trombetta di Albenga squash. Instead it became my favorite summer dish. I made it so many times this summer and now I’m getting sad thinking that I won’t be able to prepare it again until next year, because my garden is producing less and less every day.

I made few changes from the original recipe I found on America’s Test kitchen and used what is available in my garden. There are only few vegetables in this gratin: zucchini, trombetta di Albenga squash but you can use yellow zucchini, white onions and cuore di bue tomatoes flavored with garlic and fresh thyme. The vegetables are then covered by a crunchy layer of whole wheat bread, Pecorino cheese and minced shallots.

The dish doesn’t require any particular skill but a little bit of patience in preparing the vegetables. Between the preparation and the baking it takes almost two hours. It’s better not served piping hot, but rather after at least 15 minutes.  I seriously have never been able to wait that long and by the time it would be ready to be served, it’s almost always finished.

The vegetable gratin for excellence

1 lb. zucchini
1 lb. trombetta di Albenga squash or summer squash (yellow)
3-4 ripe tomatoes
2 medium onions
salt
For the aromatic oil:
1 Tbsp. finely chopped fresh thyme
2 cloves of garlic
3 Tbsp. olive oil
1/4 tsp. freshly grated white pepper
For the topping:
1 or 2 slices of whole wheat bread, 1 cup when ground
1/2 cup Pecorino cheese
1/8 cup minced shallots
chopped basil leaves (optional)

Slice the zucchini and squash 1/4 inch. thick put them in a colander over a bowl or pan, toss them with 1 tsp. salt and let them rest for 45 minutes. If you use trombetta di Albenga squash instead of summer squash, slice them paper thin.
Slice the tomatoes 1/4 inch thick and place them in a single layer on a tray covered with paper towel, sprinkle them with 1/2 tsp. salt and cover their top with an other paper towel. Let them rest for 30 minutes.
In the meantime slice the onions vertically (pole to pole) so they hold their shape better when cooking.
Heat up 1 Tbsp. olive oil, add the sliced onions, 1/2 tsp. salt and 1/4 tsp. freshly ground white pepper. The salt added to the onions before cooking helps to caramelize them easily. Cook the onions at medium heat for 20 minutes until caramelized and golden in color, mixing them quite often with a wooden spoon to avoid sticking and burning.
Heat up the oven to 400°
While the onions are cooking and the other vegetables are slowly loosing their liquid prepare the aromatic oil.
With a fork combine 3 Tbsp. olive oil, 1 Tbsp. chopped fresh thyme a 2 small garlic cloves minced and set aside.
After 45 minutes gently squeeze the zucchini to eliminate as much liquid as possible. Lastly place a little bit of zucchini and squash at the time between two layers of paper towel and press. All these passages are necessary so that the vegetables won’t release their liquid while cooking and come out soggy dish. Add 1/2 of the aromatic oil, about 2 tablespoons with the zucchini and squash and mix until well combined, hands work better than spoon here.
Gently press the tomato slices between the paper towel before removing them.
Grease a baking dish with 1 Tbsp. oil and get ready to assemble the dish. Spread the zucchini-squash mixture, cover it evenly with the caramelized onions and finish by placing the tomato slices one attached to the other in one layer. Brush the tomatoes with the rest of the aromatic oil and put the preparation in the oven.
Bake at 400° for 40-45 minutes.
While the grating is baking prepare the topping.
Finely grind the bread slices in a food processor, add 1/2 cup freshly grated Pecorino cheese, 1/8 cup minced shallots and 1 Tbsp. olive oil. Spread the bread mixture over the tomatoes, turn the oven up to 450° and bake for another 5-10 minutes until golden brown.
Let the dish cool for about 10-15 minutes. Chop few leaves of basil, sprinkle them over the top and serve.