Combine the flour, yeast, sugar, and salt in a large bowl and mix briefly.

Add the olive oil and warm water. Mix with a fork until shaggy, then turn onto a lightly floured surface.

Knead for 8-10 minutes until the dough is smooth, elastic, and springs back when pressed lightly.

Shape into a ball, place in a lightly oiled bowl, cover with a clean cloth, and leave in a warm spot for 90 minutes until roughly doubled in size.

Heat 1 tbsp olive oil in a small saucepan over medium heat. Add the crushed garlic and cook for 1 minute until fragrant but not coloured.

Add the crushed tomatoes and a pinch of salt. Simmer uncovered for 10 minutes, stirring occasionally, until the sauce thickens noticeably.

Remove the garlic, stir in the oregano, and set aside to cool completely. The sauce must be cool before you fill the panzerotti.

Drain the mozzarella cubes on paper towels for at least 30 minutes, pressing gently to remove surface moisture.

Divide the risen dough into 12 equal pieces, about 45 g each. Roll each piece on a floured surface into a disc roughly 12 cm in diameter and 3 mm thick.

Place 1 heaped tsp of tomato sauce on one half of each disc, leaving a 1.5 cm border clear. Scatter a small pile of mozzarella cubes over the sauce.

Fold the empty half of the dough over the filling to form a half-moon. Press the edges together firmly with your fingers, then run a fork along the curve twice to seal tightly.

Pour the sunflower oil into a deep, heavy saucepan and heat to 175-180 C / 347-356 F over medium-high heat. Use a thermometer for accuracy.

Carefully lower 2-3 panzerotti into the oil using a slotted spoon. Fry for 2-3 minutes per side, turning once, until they are deep golden brown and blistered on both sides.

Lift them out with the slotted spoon and set on a wire rack. Let the oil return to temperature between batches before adding the next round.

Serve immediately while the crust is still crisp and the mozzarella is molten inside.