Preheat oven to 375 degrees and line a baking sheet with parchment paper.
Spread the sweet potato and cauliflower on the prepared baking sheet. Drizzle with avocado oil. Season with pepper, curry powder, ground cumin and harissa. Toss until well-combined and spread into an even layer. Transfer to the oven and roast until the veggies are golden and tender, about 30 minutes. Taste and adjust salt to taste.
In a blender or food processor, combine the Greek yogurt, garlic, lemon juice, salt, pepper, dill and cilantro. Blend until well-combined and smooth.
To serve, spoon your choice of grain on the bottom of a bowl. Top with roasted vegetables and a dollop of the yogurt sauce. Garnish with cilantro and pine nuts.