In a large mixing bowl, whisk together 4 cups flour, 2 ¼ teaspoons yeast, and 2 teaspoons kosher salt. Pour in 1 ¾ cups warm water and ¼ cup olive oil, then mix with a wooden spoon until a shaggy dough forms. Cover and let rest at room temperature for 5 minutes.

Drizzle a little olive oil over the dough, using your hands to gently coat the surface. Cover with a damp towel or plastic wrap and let it rise at room temperature for 2 to 3 hours, or until doubled in size and bubbly.

Grease a 9x13-inch baking dish generously with olive oil. Transfer the dough into the pan and gently stretch it to fit. Let it rest for 30 minutes so it relaxes.

Preheat the oven to 425°Fahrenheit (218°Celsius). Drizzle more olive oil over the dough, then use your fingers to press deep dimples all over the surface. Press cherry tomato halves into the dough, cut side up. Sprinkle with flaky sea salt, dried oregano, red pepper flakes, and minced garlic if using.

Bake for 25-30 minutes, or until the focaccia is golden brown with crisp edges and bubbling tomatoes. Remove from the oven and let cool slightly before slicing.