Wash and dry all produce. Peel ginger, then mince until you have 2 TBSP. Melt 1 TBSP butter in a small pot over medium-high heat. Add half the minced ginger and cook until fragrant, 1-2 minutes. Add 3/4 cups water, rice, and a pinch of salt. Bring to a boil, then reduce heat to low, cover, and simmer until tender, about 15 minutes. Keep covered off heat until meal is ready.

Trim, then thinly slice scallions, separating greens and whites. Core and seed bell pepper, then cut into thin strips. Drain pineapple, reserving juice in a large bowl. Cut any large cauliflower florets into bite-size pieces. Roughly chop peanuts.

Transfer cauliflower to another large bowl. Sprinkle with a drizzle of olive oil, followed by half the cornstarch. Season with salt and pepper. Toss to coat and set aside. Heat a drizzle of olive oil in a large pan over medium-high heat. Add bell pepper and cook, tossing, until tender, 5-6 minutes. Season with salt and pepper.

Add pineapple chunks and scallion whites to pan with bell pepper. Cook until everything begins to brown, about 2 minutes more. Remove from pan and set aside. In the meantime, add vinegar, soy sauce, stock concentrate, 1 tsp sugar, 2 TBSP water, and remaining ginger and cornstarch to bowl with pineapple juice, stirring until well combined.

Heat 1 TBSP oil in same large pan over medium-high heat. Add cauliflower and cook, tossing occasionally, until browned and nearly cooked through, 3-4 minutes. Drain oil, then pour sauce into pan and let simmer until it coats cauliflower in a thick glaze, 1-2 minutes. Remove from heat, then return bell pepper mixture to pan and toss to combine.

Divide rice between plates, then top with stir-fry. Garnish with scallion greens and peanuts.