01 - Preheat oven to 425°F. Line a baking sheet with parchment paper and set aside.
02 - Toss cauliflower florets and red bell pepper slices with 1 tablespoon olive oil, a pinch of salt, and ground turmeric until evenly coated. Spread in a single layer on the prepared baking sheet. Roast for 25 to 30 minutes, turning halfway through, until the vegetables are golden brown and fork-tender.
03 - While the vegetables roast, combine rinsed rice, 2 cups water, and 1/2 teaspoon salt in a medium saucepan. Bring to a rolling boil over high heat, then reduce to low, cover tightly, and simmer for 12 to 15 minutes until the liquid is fully absorbed and the rice is tender. Remove from heat and fluff gently with a fork.
04 - In a large skillet or wok, heat the remaining 1 tablespoon olive oil over medium heat. Add the chopped onion, minced garlic, and grated ginger. Sauté for 2 to 3 minutes, stirring frequently, until the onions are translucent and the mixture is fragrant.
05 - Stir the red curry paste into the aromatics and cook for 1 minute to bloom the spices. Pour in the full can of coconut milk and soy sauce, stirring thoroughly to combine. Let the sauce simmer gently for 3 to 4 minutes until it slightly thickens and coats the back of a spoon.
06 - Add the roasted cauliflower and bell pepper to the curry sauce, tossing to coat evenly. If using baby spinach, fold it in and stir until just wilted. Squeeze fresh lime juice over the mixture and stir to incorporate.
07 - Spoon the curried vegetables over a bed of fluffy steamed rice. Finish with a generous sprinkle of chopped fresh cilantro, lime wedges on the side, and toasted cashews or peanuts if desired. Serve immediately.