How to Make It
Preheat oven to 425°F. Combine Brussels sprouts, sweet potatoes, shallots, butter, curry powder, garlic, pepper, and 1⁄2 teaspoon of the salt in a large bowl; toss to coat. Spread vegetable mixture in a single layer on a large rimmed baking sheet. Bake in preheated oven until vegetables are tender and lightly browned, 20 to 25 minutes.
While vegetables roast, bring 4 cups of the water and remaining 1⁄2 teaspoon salt to a boil in a medium saucepan over high. Add farro, and cook according to package directions; drain.
Stir together yogurt, lemon juice, and remaining 1 tablespoon water in a bowl. To serve, spoon hot cooked farro into 4 wide, shallow bowls. Divide vegetable mixture evenly among bowls; sprinkle each with pecans, and serve with yogurt mixture for topping.