In a medium saucepan cook carrot, covered, in a small amount of boiling salted water for 3 minutes. Add the peas. Return to boiling; reduce heat. Cook about 5 minutes more or until carrot and peas are crisp-tender. Drain well. Remove carrot and peas from saucepan; set aside.
In the same saucepan cook mushrooms and green onion in hot butter until tender. Stir in basil, salt, and pepper. Return carrot and peas to saucepan; heat through.