Halve the tomatoes, scoop out the seeds and watery pulp with a spoon, and dice the flesh into 1/4-inch pieces. Toss with 1/2 teaspoon fine sea salt and set in a colander over a bowl for 15 minutes. You will see a surprising amount of liquid collect underneath. Removing it is the secret to topping that stays on the bread.

Shake off the excess liquid and transfer the tomatoes to a clean bowl. Add 3 tablespoons olive oil, the balsamic vinegar, minced garlic, shallot, black pepper, and basil. Stir gently and let it sit at room temperature for 15 to 30 minutes. Taste a spoonful on a piece of bread, then adjust with a little salt or vinegar.

Heat the oven to 425°F. Slice the bread on a slight diagonal into 12 pieces, each about 3/4 inch thick. Arrange them on a baking sheet and brush both sides with the remaining 3 tablespoons olive oil. Bake for 8 to 10 minutes, flipping once halfway through. You want deep golden edges and a crisp surface, with a bit of chew left in the center. You can also grill the slices for 2 minutes per side.

While the toast is still hot, rub the cut side of the halved garlic clove lightly across the top of each slice. The rough, crisp surface works like a grater, so one clove is plenty for all 12 pieces.

Spoon about 2 tablespoons of tomato mixture onto each toast, lifting it with a slotted spoon so you leave excess marinade behind. Finish with a pinch of flaky salt and a drizzle of the marinade. Add shaved cheese if you like. Serve within 10 minutes, while the bread is still crisp. Rebecca's Tip: When tomatoes are out of season, don't use pale winter slicers. Halve cherry or grape tomatoes, toss them with a little olive oil and salt, and roast at 400°F for about 15 minutes until they are slightly blistered. Their concentrated sweetness makes up for the missing summer flavor.