1. Combine Wet Ingredients: In a large mixing bowl, whisk together the sourdough discard, warm water, 2 tablespoons of olive oil, sugar, and salt until well combined. The mixture might look a little cloudy, which is normal.

2. Add Dry Ingredients: Gradually add the all-purpose flour and instant yeast to the wet ingredients. Mix with a wooden spoon or your hands until a shaggy dough forms. It doesn’t need to be perfectly smooth at this stage, just ensure all the flour is incorporated.

3. Knead Briefly: Turn the dough out onto a lightly floured surface and knead gently for about 5-7 minutes. The dough should become smoother and more elastic. It will still be a bit sticky, which is characteristic of focaccia dough.

4. First Rise (Bulk Fermentation): Lightly grease a clean bowl with olive oil. Place the dough in the bowl, turning it once to coat. Cover the bowl with plastic wrap or a clean kitchen towel and let it rise in a warm spot for 1.5 to 2 hours, or until it has visibly doubled in size.

5. Prepare for Baking: Preheat your oven to 400 F (200 C). Generously drizzle 2-3 tablespoons of olive oil into a 9×13 inch baking pan. Gently transfer the risen dough to the prepared pan.

6. Dimple and Top: Using oiled fingertips, gently press and dimple the dough all over, creating those signature focaccia indentations. Be careful not to deflate it too much. Drizzle generously with more olive oil and sprinkle with flaky sea salt and any optional toppings like fresh rosemary or garlic powder.

7. Bake to Golden Perfection: Bake for 20-25 minutes, or until the focaccia is golden brown on top and cooked through. The crust should be crisp, and the interior soft and airy.

8. Cool and Serve: Once baked, remove the focaccia from the oven and let it cool in the pan for a few minutes before transferring it to a wire rack. Slice and serve warm.