Rinse and carefully seed chili peppers, trying to maintain shape.
Stuff jack cheese into each chili pepper.
Arrange in a 10 inch round baking dish.
In a small bowl, lightly beat eggs with a wire whip.
Beat in milk, flour, salt, and onion; pour over chili peppers.
Cover with wax paper.
Microwave on MEDIUM (50%) for 10 minutes, rotating dish 1/4 turn after 5 minutes.
Uncover and microwave on HIGH (100%) for 3 to 5 minutes (rotating dish 1/4 turn after every 1 1/2 minutes) or until center jiggles slightly when dish is gently shaken. (Upon standing, center will set.)
Sprinkle with Cheddar cheese and let stand for 10 minutes before serving.
Meanwhile, prepare tomato herb sauce; pass at the table to spoon over individual servings.
Makes about 6 servings.
Tomato herb sauce.
In a 2 cup glass measure, combine 1 small can (8 oz.) tomato sauce, and 1/4 teaspoon each garlic powder, ground cumin, and oregano leaves; stir to blend.
Microwave, uncovered, on HIGH (100%) for 2 minutes (stirring after 1 minute) or until heated through.