Japanese Seafood Risotto

Name: Japanese Seafood Risotto
Ingredients: 8 cups chicken stock; 2 tablespoons vegetable oil; 2 tablespoons finely minced ginger (about one 1-inch piece); 5 scallions, sliced, white and green parts separated; 2 cups Arborio rice; Kosher salt; 1/3 cup sake; 8 ounces small-medium shrimp, halved lengthwise (I like to use rock shrimp or Laughing Bird shrimp if available); 3/4 cup frozen shelled edamame, thawed; 2 tablespoons white miso; 1/4 cup mirin; Zest and juice of 1 lemon; 8 to 12 ounces jumbo lump crabmeat, picked through for shells; Toasted sesame oil, for garnish; Soy sauce, for garnish; Toasted shredded nori, for garnish