For the topping:

• ¹⁄₃ cup (2 oz.) cracked wheat (bulgur)
• ¹⁄₃ cup whole milk
• ¹⁄₂ tsp. kosher salt

For the casserole:

• ¹⁄₄ cup extra-virgin olive oil
• 2 carrots (5 oz.), peeled and sliced ½ inch thick, greens rinsed and reserved
• 2 garlic cloves, peeled
• 1 yellow onion (9 oz.), diced
• ¹⁄₂ large head cauliflower (1 lb.), cut into florets
• 1 large broccoli crown (1 lb.), cut into florets
• 3 cups whole milk
• 1 tsp. fresh dill, chopped
• Kosher salt and freshly ground black pepper

Instructions

1. Make the topping: Preheat the oven to 225°. In a small saucepan, add the cracked wheat, milk, and salt; bring to a boil, then reduce to a simmer. Let cook until all of the liquid has been absorbed and the wheat is tender, 15–20 minutes.
2. On a parchment paper–lined baking sheet, spread the wheat into a thin layer. Bake until crumbly, about 1 hour. Remove and let cool, then crumble the mixture into bite-size pieces. (Topping can be made up to a few days ahead and refrigerated.)
3. Make the casserole: Preheat the oven to 375° and set a rack in the center. In a large, deep, oven-safe skillet over medium-high heat, add the olive oil. Once hot, add the carrot slices, garlic, and onion; season with salt and cook, stirring frequently, until softened and lightly browned, 6–8 minutes. Add the cauliflower and cook, stirring frequently, until well browned, 12–15 minutes. Add the broccoli and season lightly with salt; lower the heat to low and cook, stirring, until browned in places, 4–5 minutes. Stir in the milk and wheat crumbs; season generously with salt and pepper.
4. Transfer the skillet to the oven. Bake until the vegetables are tender when poked with a knife and the liquid is thickened and bubbly, about 35 minutes. Sprinkle with the dill and a few sprigs of the reserved carrot greens, and serve immediately.