Prepare the dough: In a large bowl, whisk together the flour, salt, and yeast. Add water and 1 tablespoon of the olive oil and use a spoon or dough whisk (I have this one) to bring it together, stirring the mixture a few times to ensure there are no unmixed pockets of flour. Cover the bowl with plastic wrap and let it rise until it doubles and moves a lot when jiggled, about 1 1/2 hours at room temperature. If you won’t need the dough until later, you can transfer it to the fridge a little before it’s fully doubled and let it finish there for a few hours or overnight

Make the focaccia: Line a 9×13-inch or rimmed baking sheet (I use these but mine are very old) with a large piece of parchment paper that extends up the sides, pressed in. Drizzle parchment with 3 tablespoons olive oil and scrape risen dough onto it. Trying to not press any air out of the dough, use your hands, sliding them underneath a little, to gently stretch the dough once or twice towards the edges. No need to make it fill out the pan completely; it will get there on its own as it rises again. If you have one, coat a second 9×13-inch or rimmed baking sheet with olive oil and upend it over the focaccia pan to act as a lid for the rise. (If you don’t have one, use another large baking dish, like a lasagna pan. The dough needs room to grow.) Set aside for another 1 1/2 hours.

45 minutes to 1 hour later, prepare the toppings: Place sliced zucchini in one bowl and toss it with 1/2 teaspoon kosher salt. Set aside. Place sliced potatoes in a second bowl and toss them with 1 teaspoon kosher salt. Set aside. [This will soften the vegetables so they cook nicely.]

Assemble focaccia: Heat oven to 450°F. Drain zucchini and pat it dry on paper towels. Do the same with the potatoes. Carefully remove the pan covering the focaccia dough. Do not fret if the dough looks about to spill over the sides; it’s exactly right. Cover the focaccia dough with shingles of drained zucchini and potatoes (plus salami, if using), then sprinkle with rosemary needles, to taste. Drizzle focaccia with remaining 2 tablespoons of olive oil and use your fingertips to dimple the dough several times — perhaps 20 finger impressions total. Resist over-dimpling or the focaccia becomes even, flat, and boring. Sprinkle all over with flaky sea salt.

Bake focaccia: For 30 to 38 minutes, or until a deep golden brown on top and at the edges. Keep an eye on it for the last 8 minutes and try to resist pulling it from the oven too soon. When it doesn’t brown enough, the edges soften too fast.

Transfer to a cooling rack and let cool for 5 minutes, if you can bear it. Slide the focaccia out of the pan and cut into squares [especially if you’re taking it somewhere; don’t you hate cutting up food on a picnic blanket with a plastic knife?]. Enjoy!

Leftover focaccia keeps at room temperature for a few days. Rewarming it in a 350-degree oven helps re-crisp the top.

Step 1

Using a wooden spoon or rubber spatula, mix 4 cups (500 g) all-purpose flour, 1 Tbsp. Diamond Crystal or 1¾ tsp. Morton kosher salt, one ¼-oz. envelope instant yeast (about 2¼ tsp.), and 1¾ cups warm water in a large bowl just until flour is hydrated and a very shaggy dough forms, about 1 minute. Cover bowl with plastic wrap and let mixture sit at room temperature 15 minutes.

Step 2

Set a small bowl of room-temperature water on work surface for easy reaching. Uncover dough and, using a damp hand, stretch one side of dough up and over to meet opposite side; turn bowl 90°. Repeat process 3 more times, turning bowl after each fold. (This constitutes 1 full fold.) If dough doesn’t always stretch to meet opposite side, just aim for the middle. Re-moisten your hands and shake off excess water any time dough begins to feel sticky. Cover dough and let sit 30 minutes (set a timer). Repeat folding process to make 1 full fold every 30 minutes, for a total of 3 more full folds, 1 hour and 30 minutes total. By the last full fold, the dough should be significantly smoother and tighter.

Step 3

Add about half of 4 jalapeños, halved lengthwise, cut into ½” pieces, and one 8-oz. block sharp orange cheddar, cut into ½” cubes, to dough, pressing pieces in, then stretch dough over itself to evenly distribute throughout. Repeat with remaining jalapeños and cheddar. (You don’t need to be precise; some pieces will fall out.)

Step 4

Transfer dough to a generously floured surface, dust with flour, and shape into a tight round ball by cupping dough with your hands and pulling it toward you. (There should not be a ton of pieces of jalapeño or cheddar popping out; try to keep them inside as much as possible.) Dust dough with more flour. Dust a kitchen towel with flour and place in a high-sided bowl to line. Place dough, smooth side down (seam side up), on top of towel in bowl. Tightly cover bowl with plastic wrap. Let dough sit in a warm, dry spot until puffy, about 45 minutes.

Step 5

Place a rack in middle of oven and set a large Dutch oven with a lid in center of rack. Preheat to 450°.

Step 6

Place a 12×12″ sheet of parchment paper on surface. Cut a 2″ slit in each corner, cutting toward the center (this should create a sling of sorts); place on a large plate. Set parchment-lined plate upside down over bowl and very carefully turn bowl and plate over in one motion to tip dough out gently onto center of parchment (try your best not to deflate or ruin its shape). Working very quickly and using a pair of sharp scissors lightly coated in vegetable oil, cut an X in center of dough. Using parchment paper, very carefully lower dough on parchment into center of Dutch oven. Cover pot and bake bread 35 minutes.

Step 7

Remove lid from pot and reduce oven temperature to 375°. Continue to bake bread until crust is deeply browned, 60–90 minutes more. Carefully turn loaf out onto a wire rack and let cool before slicing (about 2 hours).