Preheat oven to 425 degrees.
Remove stems from mushrooms and chop up fine. Set aside.
In a medium pan, heat olive oil on medium high heat, and cook chicken sausage until no longer pink. Break into small pieces as it cooks. Set aside.
In the same pan cook scallions until wilted. Add red bell pepper and mushrooms stems and cook until both are softened. Add 1/4 cup of the white wine. Cook for another 2-3 minutes.
Add the chicken sausage back the pan.
Stir in panko crumbs and romano cheese.
Stuff each of the mushrooms with 2-3 teaspoons of stuffing making sure it is packed down and place into a medium to large casserole dish.
Pour the rest of the wine and 1/4 cup chicken stock into the bottom of the casserole dish.
Bake for 20 minutes. Serve hot.