In a medium Dutch oven over medium-low heat, melt the butter. Add the chopped green onion and sauté for 2 to 3 minutes.
Add the rice and cook on medium-low heat, stirring frequently, until rice grains are transparent, about 5 to 6 minutes.
In a medium saucepan, on medium heat, heat the chicken broth until barely simmering.
Use the ladle to add ½-cup of warm broth to the rice, stirring until most of the broth is absorbed. Repeat. Each time the rice begins to look dry, add more broth in ½ cup amounts, stirring well. Allow each addition of broth to be absorbed. Continue using all the broth and stirring the rice until the rice is creamy and thick, about 45-60 minutes. Taste the risotto for doneness.
Add the pumpkin puree and Gruyère cheese to the risotto and stir until the cheese melts. Add kosher salt to taste.
Spread the pumpkin risotto mixture in a medium Pyrex dish or half-sheet pan, smoothing it with a rubber spatula. Set aside to cool. Cover lightly with plastic wrap and refrigerate for at least two hours or overnight until cold.
Making the Pumpkin Risotto Bites
Use an ice cream scoop to scoop the risotto into 1 to 1½-inch balls. Set aside on a parchment-lined half-sheet pan. (You can refrigerate or quick-freeze the risotto balls at this point.)
Place the egg whites in one pie plate. Combine the panko crumbs, salt and pepper in another pie plate.
Dip the risotto bites first into the egg wash and then into the panko bread crumbs, coating all sides. Shake off excess panko. Place back on the half sheet.
Dip your finger in water and press into the top of the risotto balls to make more of a disk. (At this point, you can refrigerate or freeze the pumpkin risotto bites.)
In a large skillet, add oil to a depth of 1/2 inch. Heat the oil over medium-high heat until it reaches 375˚F.
Fry the risotto bites, 3 to 4 at a time, until golden brown on both sides, about 2 minutes per side. Remove with a slotted spoon. Drain on a sheet pan lined with paper towels. (After frying, you can keep them warm in a 200˚F. oven until time to garnish and serve.)
Let the risotto bites cool. Top each with 1 teaspoon crème fraîche and a green onion slice. serve immediately.
Notes
This is a great appetizer because you can quick freeze the risotto bites at different stages of preparation.