Note
1. Mix flour, semolina, salt and sugar thoroughly in the mixing bowl of the food processor.
2. Add olive oil and mix the dough for 2 minutes at a low speed until there is no loose flour in the bowl.
3. Cover the dough and leave to rise for 2 hours at room temperature (or, alternatively, overnight in the fridge).
4. Roll the sausage meat into walnut-sized balls (about 1 inch in diameter, or 2 ½ centimeters) with wet hands to make about 12 balls.

5. Warm the clarified butter in a frying pan over medium-low heat.
6. Season the mixture with salt, pepper and mustard and leave to cool slightly.
7. Brush the skillet with oil.
8. On a flour-dusted surface, divide the dough into 2 equal portions.
9. Place the pizza dough into the cast-iron skillet and press it into the bottom and up the sides.

10. Place the skillet with the dough in towards the back of the oven, letting it cook for 5 minutes.
11. Remove the skillet from the oven and top with half of your kale mixture and six mett balls.

12. Remove the skillet from the oven and let the pizza rest for 5 minutes.