In a large mixing bowl, combine the sourdough discard, warm water, honey (or sugar), and active dry yeast (if using). Whisk until the discard is mostly dissolved and the mixture is well combined.

Add the all-purpose flour and fine sea salt to the wet ingredients. Using a spatula or your hands, mix until a shaggy dough forms and no dry streaks of flour remain. Do not overmix.

Drizzle 1 tablespoon of olive oil into a clean bowl, then transfer the dough to it, turning once to coat. Cover the bowl tightly with plastic wrap or a damp kitchen towel. Let the dough rise in a warm spot for 3-4 hours, or until it has visibly increased in size and is bubbly. If not using yeast, this process might take 6-8 hours or longer, depending on the discard's activity and room temperature. You can also perform 2-3 sets of 'stretch and folds' within the first hour of bulk fermentation for better gluten development, if desired.

Drizzle 2-3 tablespoons of olive oil into a 9x13 inch (23x33 cm) baking pan. Use your hands to spread the oil evenly across the bottom and up the sides of the pan.

Gently scrape the risen dough into the prepared baking pan. With oiled hands, gently spread the dough to mostly fill the pan. Don't force it; if it resists, let it rest for 10 minutes then continue spreading. Cover the pan loosely with plastic wrap or a damp kitchen towel and let it proof again for 30-60 minutes in a warm spot, or until puffy and light. Preheat your oven to 425°F (220°C) during the last 15 minutes of this proof.

Once the dough is puffy, drizzle the remaining 1-2 tablespoons of extra virgin olive oil over the surface. Use your fingertips to gently dimple the dough all over, pressing down to create characteristic focaccia indentations. Sprinkle the chopped fresh rosemary, sliced garlic, and flaky sea salt evenly over the dimpled surface.

Place the focaccia in the preheated oven and bake for 25-30 minutes, or until deeply golden brown on top and cooked through. The bottom should also be golden and crisp.

Once baked, carefully remove the focaccia from the oven. If you like an extra crispy bottom, slide it out of the pan and onto a wire rack immediately. Let it cool for at least 15-20 minutes before slicing and serving. This Sourdough Discard Focaccia is best enjoyed warm.