Step 1

Place a rack in the center of your oven and preheat the oven to 400 degrees F. Liberally coat a rimmed baking sheet with nonstick spray and set aside.

Step 2

Place the onions and sweet potatoes on the baking sheet, turning the sweet potatoes cut sides up. Drizzle with 2 teaspoons olive oil, making sure the flesh of the sweet potatoes is well coated. Sprinkle with 1 teaspoon chili powder, 1/4 teaspoon salt, and 1/4 teaspoon pepper. Rub and toss to coat, and then arrange on the baking sheet. Bake for 10 minutes.

Step 3

While the sweet potatoes cook, chop the broccoli or cauliflower into florets (you should have about 5 cups total). Remove the baking sheet from the oven and flip the sweet potatoes so that they are cut sides down. Push the sweet potatoes and onions to one side and add the cauliflower or broccoli to the open side of the pan. Drizzle with 2 teaspoons olive oil and sprinkle with 1/4 teaspoon salt, 1/4 teaspoon pepper, and the remaining 1 teaspoon chili powder. Carefully toss to coat, and then return the baking sheet to the oven. The pan will be very crowded, and the veggies will overlap somewhat. Return to the oven and bake for an additional 20 to 25 minutes, until the sweet potatoes are soft and the other vegetables are crisp-tender.

Step 4

Remove the sheet pan from the oven and place the kale on top of the vegetables. Drizzle the kale with the remaining 2 teaspoons olive oil and sprinkle with the remaining 1/4 teaspoon salt and 1/4 teaspoon pepper. Lightly rub the kale to coat, and then arrange the kale in a single layer over the whole pan. Return the pan to the oven and bake for 5 additional minutes, until the kale is very lightly crisp and softened. Remove the whole pan from the oven and set it aside to cool.

Step 5

While vegetables finish roasting, prepare the dressing: Add the lemon juice, tahini, garlic, cumin, and salt in a small mixing bowl. Add 2 tablespoons hot water. Whisk to combine. Taste and add additional salt and up to 1/2 teaspoon additional cumin as desired.

Step 6

To serve: Once the vegetables are cool enough to handle, cut the sweet potatoes into bite-size pieces. Roughly chop the kale. Divide the vegetables among serving bowls. Slice the hardboiled eggs in half and place 2 halves on top of each bowl. Drizzle with tahini dressing and enjoy immediately.