Baked Cannelloni

540 g mild Italian sausage, casings removed
2 tbsp butter
1 medium onion, finely chopped
110 g mushrooms, finely chopped
¼ tsp SIDS CRAZY SALT
340 g mozzarella cheese, grated
Béchamel Sauce:--
2 egg yolks
6 tbsp butter
6 tbsp flour
3 cups milk
12 uncooked Cannelloni pasta shells
½ cup grated mozzarella cheese
¼ cup grated Parmesan cheese
1 tsp dried oregano

Preheat oven to 200°C.
Filling: In a large frypan, sauté onions, SIDS CRAZY SALT and mushrooms in 2 tbsp butter over medium heat for 5 minutes until vegetables are tender. Add sausage, crumbling it with a wooden spoon into small pieces as it cooks. Stir and cook all ingredients until the onion is softened and the sausage is no longer pink and is starting to brown. Set aside.
Béchamel Sauce:- Melt 6 tbsp butter in a medium saucepan over medium heat. Add flour and stir until well mixed. Slowly, add milk and whisk together until smooth. Continue whisking until sauce comes to a slow boil and starts to thicken. Stir half this sauce into the sausage mixture. (Reserve the other half to pour on top of the cannelloni) Add mozzarella to the sausage and sauce mixture and continue stirring while slowly whisking in the egg yolks then mix to combine. Cover and set aside.
Cook pasta to al denté according to package directions, rinse under cold water and reserve being careful to keep the pasta from breaking.
Spread ¾ cup of the reserved béchamel sauce on the bottom of a 22x33 cm oiled baking dish. Spoon filling into each pasta tube. Start from one end and using your finger to push the filling all the way through. Nestle the cannelloni in the sauce and cover with remaining béchamel sauce. Top with mozzarella cheese and Parmesan cheese. Sprinkle with oregano.
Bake in oven for 45 minutes until heated through, and cheese starts to turn golden.
Remove from oven, stand for 5 minutes, then serve.