Step 1

Toss radishes, cucumbers, and vinegar in a medium bowl; season with salt. Gently massage vegetables with your hands to soften. Let marinate until ready to use.

Step 2

Thinly slice 8 scallions. Melt butter in a medium pot over medium heat until foaming. Add garlic, ginger, and sliced scallions and cook, stirring often, until tender and golden, 8–10 minutes. Stir in oats and cook, coating the grains in the aromatics, until warmed through, about 2 minutes. Add dashi powder and 5 cups water. Increase heat to high and bring to a boil, then reduce heat to medium-low and cook, stirring occasionally, until oats are tender and liquid is thick and creamy, 30–35 minutes.

Step 3

Slice remaining 4 scallions on a diagonal and toss with pickled vegetables.

Step 4

Divide oats among bowls. Arrange crunchy veg on top and drizzle with any liquid that remains in bowl. Drizzle with chili oil and top with peanuts.