Combine the instant dry yeast, honey, and lukewarm water in a medium bowl and let sit 5 minutes (it should foam or bubble up a bit). Then add flour and 5 teaspoons of crystal salt or 1 tablespoon of granulated salt and mix until it starts to form a shaggy dough, and all the flour has been incorporated into the mixture.

Pour 4 tablespoons extra-virgin olive oil into a big bowl that will fit in your refrigerator — make sure the bowl has plenty of room for the dough to rise. Transfer dough to the bowl and turn to coat it in oil. Cover with a damp towel and store in the refrigerator, until it has doubled in size (it should look very bubbly and alive), at least 8 hours, or let it rise at room temperature until doubled in size, approximately 4 hours.

Butter an 18x13" rimmed baking sheet, then pour 1 tablespoon of olive oil into the pan. Coat your hands in olive oil, then lift the base of the dough from the edge and fold it over itself. Do this two more times, turning the bowl as you go to gently deflate the dough and form a loose ball shape. Transfer the dough into the baking pan, gently stretch the dough out to fill the pan up most of the way (it will continue to spread out a bit as it rises), and drizzle any remaining oil left in the bowl over it. Let the dough rise one more time in a dry, warm spot until doubled in size, usually 2-4 hours.

While the dough is rising, preheat your oven to 450℉. Prepare a baking sheet with your sliced tomatoes and roast for approximately 20 minutes to cook out some of the water and concentrate the tomato flavor. Set the tomatoes aside and allow to cool.

Lightly oil your hands. Dimple focaccia all over with your fingertips, creating deep depressions in the dough. Drizzle with remaining 1 tablespoon extra-virgin olive oil, top with your slices of roasted tomatoes (or other cooked vegetables), freshly ground black pepper, garlic (if desired), and sprinkle with flaky sea salt. Bake focaccia until puffed and golden brown all over, 20–35 minutes.