1Heat oven to 400°F. Spray 9-inch glass pie plate with cooking spray.
2In 10-inch skillet, cook beef and onion over medium heat 8 to 10 minutes, stirring occasionally, until beef is brown; drain. Stir in salt. Spread in pie plate. Sprinkle with cheese.
3In small bowl, stir remaining ingredients with fork or wire whisk until blended. Pour into pie plate.
4Bake about 25 minutes or until knife inserted in center comes out clean.