In a large mixing bowl, mix the strong bread flour, salt, yeast, and granulated sugar until well combined.

Gradually pour in the warm water while stirring until a dough begins to form.

Dust a clean surface with flour and knead the dough for about 10 minutes, until it's smooth and elastic.

Place the kneaded dough in a lightly oiled bowl, cover it with a cloth, and let it rise in a warm space until it has doubled in size, approximately 1 hour.

While the dough is rising, preheat your oven to 220°C (428°F).

Once risen, punch down the dough gently and knead in the chopped kimchi, crispy bacon (if using), and spring onions.

Shape the dough into a rectangle and transfer it onto a baking tray that’s sprinkled with semolina or polenta.

Using your fingertips, create dimples all over the surface of the dough, then drizzle with olive oil.

Let the dough rest for an additional 30 minutes.

Place the tray in your preheated oven and bake for about 30 minutes, or until the bread is golden brown.

Once baked, allow the focaccia to cool slightly before slicing and serving.