Preheat the oven to 425oF and line a large sheet pan with parchment paper.

Combine 3 cups water and the lentils in a small pot and bring to a boil over medium-high heat. Cover, reduce the heat to low, and cook until the lentils are just about tender, about 20 minutes. Drain and rinse with cold water for 45 to 60 seconds, then transfer to a large bowl.

Meanwhile, add the sweet potatoes and cauliflower to a large bowl and toss with the oil, garlic, salt, and black pepper. Transfer to the sheet pan in one even layer. Bake until the sweet potatoes are crisp and fork tender, 20 to 25 minutes.

Add the cooked lentils to the same sheet pan. Mix in the balsamic vinegar and honey, gently toss, and spread everything in one even layer. Return to the oven until the lentils, sweet potatoes, and cauliflower are very crisp, another 15 to 20 minutes.

While it bakes, prepare the balsamic tahini sauce: In a small bowl or jar, whisk together the balsamic vinegar, tahini, olive oil, honey, garlic powder, and a pinch of kosher salt and black pepper until smooth. Whisk in 1 tablespoon of warm water to thin it out. Taste and add additional salt and pepper if desired.

To serve, divide the sheet pan components between 4 bowls and drizzle each with the balsamic tahini sauce. Top each one with crumbled feta (if using) and sprinkle with chopped dill. Serve each bowl with a lemon wedge and squeeze the juice over everything right before enjoying.