Step 1

Bring ginger, sesame oil, vegetable oil, red pepper flakes, and paprika to a gentle simmer in a small saucepan over medium heat. Let bubble gently 30 seconds, then remove from heat. Add sesame seeds, mirin, raw sugar, miso, sake, and Sichuan peppercorns and whisk until sugar is dissolved. Return paste to a gentle simmer, then let cool.

Step 2

Do Ahead: Sichuan chili paste can be made 1 month ahead. Cover and chill.

Step 3

Cook scallions, ginger, apple, garlic, miso, mirin, sake, toban djan, and red pepper flakes in a small saucepan over medium heat, stirring, just until warm (do not let it simmer) and garlic no longer tastes raw, about 5 minutes.

Step 4

Do Ahead: Miso tare can be made 1 month ahead. Let cool; cover and chill.

Step 5

Heat oil in a small saucepan over medium-high until very hot but not quite smoking. Add scallions and paprika; season with salt. Cook, swirling pan often, until scallions are browned and oil is deep red, about 2 minutes. Let cool.

Step 6

Do Ahead: Chili oil can be made 1 month ahead. Cover and chill.

Step 7

Cook noodles in a large pot of boiling salted water according to package instructions until al dente. Drain, then immediately chill in a bowl of ice water. Drain again.

Step 8

Toss cucumbers, bell pepper, and radishes with 3 Tbsp. Sichuan chili paste in a small bowl until well coated. Season to taste with salt. Toss in basil.

Step 9

Whisk miso tare into milk in a medium bowl, then whisk in grapefruit zest and soy sauce.

Step 10

Divide noodles, then milk mixture and vegetables, among bowls. Toss granola or other crunchy toppings of choice in a little chili oil in a small bowl and scatter over noodles; drizzle with more chili oil.