This boldly flavored bread, developed by cookbook author Leah Koenig, is a great use for not-too-sweet strawberries, which caramelize and intensify in flavor while cooking. The onion and balsamic vinegar add a welcome tartness—try slices drizzled with additional olive oil or spread with fresh goat cheese.
- 2¼ tsp. (one ¼-oz. packet) active dry yeast
- 1 tsp. honey
- ¾ cup plus 1 Tbsp. extra-virgin olive oil, divided
- 2½ cups all-purpose flour, plus more for kneading
- 1 tsp. kosher salt
- 1 medium sweet onion, quartered and thinly sliced
- 2½ tsp. balsamic vinegar
- 1½ tsp. maple syrup
- 1 cup strawberries, hulled and sliced lengthwise into 1/8-inch pieces
- Flaky sea salt
- 8–10 fresh basil leaves, thinly sliced
In a medium bowl, add the yeast, 1 cup lukewarm water (100–110°F), and the honey; stir to combine. Set aside just until foam forms on the surface of the liquid, about 5 minutes, then add ¼ cup oil, followed by the flour and salt. Using a fork, stir until a dough forms, then turn out onto a lightly floured work surface. Knead until the dough is smooth and supple, about 10 minutes, then form into a ball. Lightly grease a large bowl with 1 tablespoon oil, then add the dough, cover with plastic wrap, and set aside to rise until the dough has just slightly more than doubled in size, about 1 hour.
Brush a 9-by-13-inch rimmed baking sheet with 2 tablespoons oil. Transfer the dough to the baking sheet, and using your fingers, spread the dough out to the edges. Using your fingers, press the dough all over to form dimples. Drizzle 2 tablespoons oil over the top, then cover loosely with plastic wrap and set aside to rest until the dough puffs up slightly, about 30 minutes.
Meanwhile, in a large skillet over medium-low heat, add 1 tablespoon oil. When the oil is hot, add the onion and cook, stirring occasionally, until very soft and lightly browned, 15–20 minutes. Add the vinegar and maple syrup; cook until the liquid has evaporated, 2–3 minutes more. Remove from the heat and let cool to room temperature.
Set a rack in the center of the oven and preheat to 450°F. Distribute the strawberries across the top of the dough, pressing them down slightly, then scatter the onions evenly across the top. Drizzle the remaining 3 tablespoons oil over the top and sprinkle with flaky salt to taste. Bake until the focaccia is golden at the edges and browned on the bottom, about 20 minutes. Remove from the oven and let cool slightly before using an offset spatula to slide the focaccia onto a cutting board. Top with the basil, then let cool completely. Cut into pieces and serve.