Make the dough: In a bowl, mix the flour, dried yeast, oregano, and 1½ tsp sea salt.
Add 2 tbsp olive oil and 200ml (¾ cup + 1 tbsp) warm water, then knead until smooth (I used my stand mixer). Cover and let rise for 45 minutes.
Prepare the topping: Chop one small red onion very finely.
Add the onion to a bowl and mix with the ground Parmigiano Reggiano and a pinch of sea salt.
Preheat oven and pan: Heat the oven to 220°C (425°F) and grease a six-hole muffin pan with olive oil.
Shape the buns: Divide the dough into six portions and place in the pan. Press down slightly and let rest 15 minutes.
Top and bake: Drizzle olive oil over each bun, press gently with your fingers to create little pockets, and sprinkle with the onion-parmesan mixture. Bake 15 minutes until golden.
Serve: Cool slightly before enjoying warm with butter or serve with your favourite lunch.