Bring 3 cups broth to simmer in small saucepan. Reduce heat to very low; cover and keep warm.
Heat olive oil in heavy medium saucepan over medium heat.
Add onion; sauté until translucent, about 5 minutes.
Add rice; stir 1 minute.
Add wine; stir until absorbed, about 30 seconds.
Add broth, 1/3 cup at a time, and simmer until rice is just tender and risotto is creamy, allowing broth to be absorbed before adding more, and stirring often, about 18 minutes.
Remove from heat.
Mix in 6 tablespoons Parmesan and butter. Season generously with salt and pepper.
Spread risotto in 13x9x2-inch pan and cool completely.
Mix 1/2 cup panko, Fontina cheese, parsley, chopped chives, and 1 egg yolk into risotto. Shape into 1 1/4-inch balls; flatten to 2-inch rounds. Arrange on rimmed baking sheet. (Can be made 2 days ahead. Cover and refrigerate.)
Preheat oven to 250°F. Set another rimmed baking sheet in oven. Beat 2 eggs in shallow bowl to blend.
Place 1 cup panko in another shallow bowl. Dip risotto cakes into beaten egg, then into panko to coat.
Pour enough canola oil into large skillet to coat bottom; heat oil over medium-high heat. Working in batches, sauté risotto cakes until crisp and brown, about 2 1/2 minutes per side.
Transfer to baking sheet in oven.
Serve risotto cakes sprinkled with cheese and garnished with chives.
These cakes owe their delicate, crisp coating to panko, which have a coarser, lighter texture than regular dried breadcrumbs.
