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

Slowly pour in the warm water while stirring, until a shaggy dough forms.

Transfer the dough onto a floured surface and knead it for about 10 minutes.

Place the dough in a lightly oiled bowl, cover it with a cloth, and let it rise in a warm spot until it doubles in size—around 1 hour.

Preheat your oven to 220°C (428°F) while the dough is rising.

After the dough has risen, punch it down and knead in the chopped kimchi, bacon (if using), and chopped spring onions.

Shape the dough into a rectangle and place it onto a baking tray sprinkled with semolina or polenta.

Use your fingertips to create dimples all over the surface of the dough, then drizzle it generously with olive oil.

Let the dough rest for another 30 minutes.

Slide your dough into the preheated oven and bake it for about 30 minutes.

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