In the meantime, put together your onions: Warmth a big sauté pan over medium warmth. As soon as sizzling, add 2 tablespoons olive oil. As soon as the oil is heated, add the onions and 1 teaspoon kosher salt. Prepare dinner onions, stirring each minute or two, till a medium brown, virtually caramel coloured, about 25 minutes. [See Note at end.] Scrape onions onto a plate to chill whilst you end the bread.
End the focaccia: When the dough is doubled, pour 2 tablespoons olive oil right into a 9×13 cake pan. Don’t deflate your dough, simply scrape it into the oiled pan. Drizzle the highest of the dough with one other tablespoon of olive oil and use your fingers to dimple the dough, flattening it out. It’s okay if it doesn’t attain the sides. Let the dimpled dough relaxation at room temperature for quarter-hour and warmth your oven to 425°F. After quarter-hour, dimple the dough solely the place wanted a little bit additional into the corners. Let relaxation for a last quarter-hour earlier than scattering the highest with onions, poppy seeds, and some pinches of salt.
Bake the focaccia: For 25 minutes, till deeply golden brown on the edges and throughout the highest. Whereas it bakes, you’ll be able to put together any toppings you’d wish to serve it with, corresponding to cream cheese or butter, lox, thinly sliced tomatoes, cucumbers, onions, or capers.
To serve: Loosen the focaccia if it’s caught in anyplace and slide it right into a reducing board. Lower into 12 squares, utilizing a pointy knife to get by way of the onions on prime with out pulling them off, and changing any that scatter. Eat immediately.
Do forward: Focaccia retains at room temperature for 1 to 2 days. Reheat on a baking sheet at 350°F for 10 to 12 minutes.
Be aware: These will not be caramelized onions; we don’t want 60 to 90 minutes over low warmth with fixed stirring. That’s not how any ancestor of mine cooked onions. I’m deliberately utilizing the next warmth for extra rapidly developed taste. In the event that they’re not selecting up shade by 20 minutes, bump up the warmth barely. In the event that they’re coloring too quick to make it to twenty to 25 minutes, cut back the warmth. We need to stopping shy of a darkish bronzed shade, because the onions will end within the oven and we don’t need them to burn.