1. Prepare gnocchi: In large bowl, mix first 5 ingredients, 3/4 cup flour, and 1/2 teaspoon salt. Onto waxed paper, measure 2 tablespoons flour. With floured hands, shape ricotta mixture into 1-inch balls. Roll balls in flour to coat evenly.
2. Meanwhile, fill 5-quart saucepot half full with water; add 1 teaspoon salt if desired. Over high heat, heat to boiling. Carefully add gnocchi, half at a time, to boiling water; cook 10 minutes, stirring occasionally, until gnocchi are slightly puffed and set. With slotted spoon, remove gnocchi to paper towels to drain.
3. In 2-quart saucepan over medium heat, melt butter or margarine; stir in 3 tablespoons flour and 1/8 teaspoon salt; cook 1 minute. Gradually stir in milk; cook, stirring frequently, until sauce thickens slightly. Remove saucepan from heat; stir in fontina until it melts.
4. Preheat broiler if manufacturer directs. Into shallow 2-quart casserole, spoon small amount of cheese sauce; arrange gnocchi on sauce; spoon remaining sauce over and around gnocchi. About 7 to 9 inches from source of heat (or with oven control set at 450°F.), broil gnocchi 5 to 7 minutes until hot and bubbly.