Garlic and thyme are perfect partners for the juicy cherry tomatoes that top this easy focaccia. Minimal dough handling means the bread requires just 15 minutes of prep.
In a large bowl, whisk together flour, yeast, sugar, 1 tablespoon salt, and 1 tablespoon thyme. Add cold water and 1/3 cup oil. Stir with a wooden spoon or your hands until a wet dough forms and no dry flour remains. Cover bowl with plastic wrap and let rise at room temperature until dough quadruples in volume and top appears bubbly, at least 12 hours and up to 18 hours.
Pour 1/3 cup oil onto a 12-by-18-inch rimmed baking sheet. Lightly coat your hands with oil on sheet, and scrape dough onto center of sheet. Turn dough to evenly coat with oil, then press to spread in an even thickness to edges of pan. Use your fingers to make dimple-like indentations all over dough. Cover and let rise at room temperature until doubled in volume (dough should reach top of sheet rim), about 1 1/2 hours.
Preheat oven to 500 degrees with rack in lower third. In a bowl, toss tomatoes with garlic, red-pepper flakes, and remaining 1 tablespoon oil, 2 teaspoons thyme, and 1 teaspoon salt. Sprinkle evenly over dough; drizzle with any accumulated juices from bowl.
Bake until puffed slightly and golden brown on top, 16 to 18 minutes (if top is browning too quickly,tent with foil). Let focaccia cool in pan on a wire rack until warm but no longer hot, about 20 minutes. Serve warm or room-temperature, or let cool completely and store in an airtight container at room temperature up to 2 days.