Indoor S’mores Bars

8 cups grahams cereal

1 bag (10 oz) miniature marshmallows (5 1/2 cups)

1 1/2 cups milk chocolate chips (9 oz)

5 tablespoons butter or margarine

1/4 cup sugar

1 tablespoon water

1 teaspoon vanilla

Grease 13x9-inch pan with butter. Measure cereal into large bowl. Reserve 1 cup of the marshmallows. In 3-quart saucepan, heat remaining 4 1/2 cups marshmallows, the chocolate chips, butter, sugar and water over low heat, stirring occasionally, until completely melted. Remove from heat; stir in vanilla. Pour marshmallow mixture over cereal in bowl; stir until evenly coated. Stir in remaining 1 cup marshmallows. Press firmly in pan. Cool at least 1 hour until firm. For bars, cut into 6 rows by 4 rows. Store loosely covered at room temperature.