Preheat oven to 375°F or preheat grill. Place potatoes in a large pot of cold water with 2 tablespoons salt then bring to a gentle boil. Cook for 10 minutes, or until potatoes are just tender. Drain and set aside to cool.

Cut tomatoes in about ¼-inch pieces, place in a bowl and sprinkle with a generous pinch of salt. Using the flat side of a large knife, smash the garlic clove against the cutting board to make a paste. When smooth, mix into the tomatoes with 2 tablespoons olive oil and ¼ teaspoon salt. Let sit at room temperature while preparing fish.

Roll out 2 pieces strong (or double-layered) aluminum foil about 2 feet long and fold each in half. Open again and using the left half only (the “bottom”), lay out 10 slices zucchini, 10 potatoes, 2 pieces fish, lemon zest, thyme, ¼ cup water, olive oil and a few drops of lemon juice. Season entire contents generously with kosher or flaky sea salt (and pepper if desired). Fold over the “top” and then pinch each side, folding ¼ inch of foil, twice, to make a tight seal for your pouch. Make a second pouch with the remaining ingredients.

Transfer pouches to a large sheet pan and bake for 15 to 18 minutes (otherwise place pouches on a hot grill for approximately 12 minutes). Each pouch should puff up with steam after several minutes. Remove from the oven (or grill) and let sit for 5 minutes (be careful of escaping steam when opening foil pouch). Fish is cooked when pierced easily with a fork. To the tomatoes slowly add remaining lemon juice to desired taste plus more salt if needed. Divide pouch contents among 4 warm dinner plates and finish by topping with the tomato vierge and torn basil leaves.