Cook spinach according to package directions.
Drain well; let cool.
Squeeze spinach very dry.
Chop spinach very fine; place in medium bowl.
Stir in ricotta cheese.
Add eggs; mix well.
Add 1/3 cup (80 mL) of the Parmesan cheese, 3 tablespoons (45 mL) of the flour, the salt, pepper and nutmeg; stir to mix very well.
Refrigerate covered 1 hour.
Spread remaining 1 cup (250 mL) flour in shallow baking pan.
Press a heaping tablespoonful of spinach mixture between spoon and hand to form oval gnocchi; place on flour.
Repeat until all spinach mixture is used.
Roll gnocchi lightly in flour to coat evenly; discard excess flour.
Slip 8 to 12 gnocchi into large kettle of boiling salted water; reduce heat to medium.
Cook uncovered until gnocchi are slightly puffed and medium-firm to the touch, about 5 minutes.
Remove gnocchi with slotted spoon to paper towel-lined plate; then transfer immediately to greased flameproof shallow baking dish.
Reheat water to boiling.
Continue cooking and draining gnocchi in batches until all have been cooked.
Arrange gnocchi so that they are in single layer in baking dish.
Heat broiler.
Melt butter in small saucepan.
Spoon butter over gnocchi; sprinkle with remaining 1/3 cup (80 mL) Parmesan cheese.
Broil gnocchi, 5 inches (13 cm) from heat source, until cheese topping is light brown, 2 to 3 minutes.