Directions

1. Make the filling: In a large skillet over medium heat add olive oil, onion and mushroom cook for 5 minutes allowing the onion to soften and the mushrooms to release liquid.
2. Once most of the liquid has dissipated, 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.
3. To make a béchamel sauce: Melt butter in a medium saucepan over medium heat. Add flour and stir until well incorporated. 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 cubed mozzarella to the sausage and sauce mixture and continue stirring while slowly whisking in the egg yolks; mix to combine cover and set aside.