Step 1 – Clean tripe and remove excess fat and soak in vinegar and salt for 4 hours. Strain tripe and cook in a pressure cooker with water, celery and parsley for 40 minutes or until tender. Once cooked, strain then cut into strips and refrigerate.
Step 2 – Soak bread in milk until soft. Set aside.
Step 3 – Heat oil in a frying pan and sauté onion and garlic until translucent. Add fresh oregano and the previously chopped tripe.
Step 4 – Bring to a boil. Add the bread soaked in milk, removing any excess milk. Season with salt and cook for 5 minutes.
Step 5 – Divide the mixture into buttered clay bowls. Sprinkle grated Parmesan on top of each and bake for 10 to 12 minutes at 180°C (350°F).