Toss together first 6 ingredients in an aluminum foil-lined jellyroll pan.
Bake at 450° for 20 minutes or until tomatillos and tomatoes are tender. Remove from oven; reduce oven temperature to 375°.
Stir together egg yolks and next 7 ingredients in a large bowl; stir in tomatillo mixture and cheese. Pour into a lightly greased 11- x 7-inch baking dish.
Bake at 375° for 40 to 45 minutes or until set and wooden pick inserted in center comes out clean. Let stand 10 minutes before serving.