Combine potatoes and sauce mix in 1 1/2 quart baking dish.
Stir in boiling water, milk, and margarine or butter with whisk.
Mix in pesto, tomatoes and artichoke hearts, if using.
Bake uncovered for 20 minutes. Top with cheese and bake 5 more minutes, or until top is golden brown and potatoes are tender (sauce will thicken slightly when cooling).
Remove from oven and let stand a few minutes before serving.