1Heat oven to 375°F. In 10-inch skillet, cook beef over medium-high heat 6 to 8 minutes, stirring occasionally, until thoroughly cooked; drain. Stir in ketchup, mustard and onion.
2In small bowl, stir Bisquick mix and boiling water with fork until dough forms. Divide dough into fourths. On surface sprinkled with Bisquick mix, roll dough pieces in Bisquick mix to coat. Press each piece into 6-inch round, 1/4 inch thick.
3Spoon 1/4 cup beef mixture onto one side of each dough round to within 1/2 inch of edges. Top beef on each round with 1/4 cup cheese and 3 pickle slices. Fold dough in half, covering filling. Press edges with tines of fork to seal.
4On ungreased cookie sheet, place calzones. Brush with egg; sprinkle with sesame seed. Bake 15 to 20 minutes or until golden brown.