In a medium skillet over high heat, bring wine, chicken broth and bay leaf to a boil. Slide in chicken breasts. When liquid returns to a boil, lower to a simmer; gently poach chicken until cooked through, 10 to 12 minutes.
Preheat a second skillet over high heat. Add oil and butter. When butter has melted into oil, add mushrooms, onions, salt and pepper, and cook until tender, 5 minutes. Whisk in flour and cook another minute, stirring.
Remove chicken from broth and set on a cutting board. Ladle 2 to 2 and 1/2 cups cooking liquid into the mushrooms, whisking it in; discard bay leaf. Add pimentos and peas to the sauce. Dice chicken into bite-sized pieces and slideinto the bubbling sauce. Adjust salt and pepper to taste.
Split large, warm biscuits and place bottoms on dinner plates and cover with ladles of chicken a la king, then top cap with biscuit tops and garnish with chopped parsley.