Artichoke Casserole

1 clove garlic, minced
1/4 cup chopped scallions
2 tablespoons parsley
1/4 cup olive oil
1 rounded tablespoon flour
3/4 cup milk
1 (13 3/4 ounce) can artichoke hearts, cut up
1/2 cup shredded sharp Cheddar cheese
1/2 cup grated Parmesan cheese

Saut