Step 1 Combine chicken and balsamic vinegar in a bowl and refrigerate.
Step 2 Pour 1 tablespoon boiling water over sun-dried tomatoes and set aside. Cook pasta following packet directions. Drain and return to saucepan to keep warm.
Step 3 Once pasta is cooked, drain chicken, reserving marinade. Add 1/4 cup stock to marinade and set aside.
Step 4 Heat oil in a large frying pan. Sautée; half the chicken for 1-2 minutes until browned. Remove and repeat with remaining chicken.
Step 5 Add remaining stock to pan with onion and rosemary and sautée; for 3 minutes. Add garlic, mushrooms and asparagus and sautée; for a further 3 minutes. Add chicken, marinade and tomatoes and stir for another minute or until chicken is cooked through.
Step 6 Remove from heat and add spinach, cream and parsley and stir until spinach has wilted. Stir sauce through warm pasta and serve immediately.