On a sheet of waxed paper, combine the flour, 1/4 teaspoon of the salt, and 1/4 teaspoon of the pepper

Dredge the sausage in the flour mixture, shaking off the excess

Spray a large saucepan or Dutch oven with non-stick cooking spray, add the oil, and heat until hot but not smoking over medium heat

Add the sausage and cook, stirring frequently, until lightly browned, about 5 minutes. With a slotted spoon, transfer the sausage to a plate and set aside

Add the shallots and garlic to the pan and cook, shaking the pan frequently, until the mixture is lightly golden, about 2 minutes

Add the potatoes, mushrooms, and carrots, stirring to coat

Stir in the broth, lemon juice, tarragon, remaining 1/4 teaspoon salt, and remaining 1/4 teaspoon pepper

Bring to a boil, reduce to a simmer, cover, and cook until the potatoes and carrots are tender, about 15 minutes. Return the sausage to the pan along with the peas and scallions and stir well to combine

Simmer, uncovered, until the chicken is cooked through and the peas are hot, about 3 minutes longer

Stir in the parsley and serve.