Prepare rice according to package directions. While still hot, stir in butter and Parmesan cheese; let cool completely. Ensure that the rice is completely cooled.
Stir in eggs, 1/2 cup (125 mL) of the bread crumbs and parsley.
Roll 1/4 cup (60 mL) of the rice mixture into a ball. Hollow out the centre to create a space for the filling; place one cube of mozzarella in centre of ball. Reshape the rice to enclose the filling. Repeat to make 18 rice balls; roll in remaining bread crumbs.
In deep saucepan, pour enough oil to come about 4 inches (10 cm) up side of pan; heat to 350˚F. Fry rice balls, in batches, for 3 or 4 minutes or until golden brown.