Preheat oven to 475°. Toss together cauliflower, mushrooms, 2 1/2 Tbsp. oil, 1/2 tsp. cumin, 1/2 tsp. salt, and 1/8 tsp. pepper in a medium bowl. Spread cauliflower mixture in a single layer in jelly-roll pan.
Toss together sweet potatoes, 2 1/2 Tbsp. oil, and remaining cumin, salt, and pepper. Spread in a single layer in another jelly-roll pan.
Bake potatoes and cauliflower at 475° for 10 to 12 minutes or until browned and just tender, turning once. Cool on wire racks 10 minutes.
Reduce oven temperature to 375°. Heat remaining 1 Tbsp. oil in a large skillet over medium-high heat. Add garlic; cook, stirring often, 1 minute. Add kale; cook, stirring occasionally, 10 minutes or until tender. Add salt and pepper to taste; stir in vinegar.
Layer half each of sweet potatoes, cauliflower mixture, beans (if desired), kale, and 1 1/2 cups Easy Cheese Sauce in a lightly greased 13- x 9-inch baking dish. Repeat layers once. Top with remaining 1/2 cup cheese sauce. Stir together panko, chopped cilantro, and olive oil, and sprinkle crumb mixture over casserole.
Bake at 375° for 20 to 25 minutes or until thoroughly heated, bubbly, and golden brown. Let stand 5 minutes before serving.
Great healthy side or vegetarian main course. The prep can be done night before them put together and baked before a party or holiday meal. It does freeze wel. I've cooked this once as a vegetarian main course and it gets requested as a super-side every holiday now. Wonderful texture and taste with no guilt.
This could well be called "Superfood Casserole", as it covers all the major veggie groups and even the fungus...a tasty dish, although the sweet potato seemed the outlier in the flavor profile. I would decrease the proportion or use a winter squash (i.e., something less sweet) next time. For the cheese sauce I used a mix of 1% and whole milk and reduced the jack (non-pepper) by half, adding an ounce of Neufchatel for creaminess. I did include the lima beans, adding them frozen to the kale during the cooking step, and adding the garlic last to preserve its flavor. No side needed but a whole-grain roll. There was a fair amount of prep work involved but with the above tweaks I would make this again.