Use regular broccoli instead of broccoli rabe for a more kid-friendly version.
1 tablespoon olive oil
2 garlic cloves, thinly sliced
1/2 teaspoon crushed red pepper flakes
1 medium bunch broccoli rabe (rapini), trimmed, cut into 1/2-inch pieces
2 teaspoons kosher salt plus more
1/2 teaspoon freshly ground black pepper plus more6 large eggs
1 1/2 cups whole milk
1/2 pound country-style white bread, cut into 1-inch pieces (about 8 cups)
1/2 cup plus 2 tablespoons finely grated Parmesan
6 thin slices pancetta (Italian bacon)
Preheat oven to 350°. Heat oil in a large skillet over medium heat. Add garlic and red pepper flakes. Stir until garlic is softened, about 30 seconds. Add broccoli rabe; sea-son with salt and pepper.
Cook, tossing, until wilted, about 2 minutes; let cool slightly.Meanwhile, whisk eggs, milk, 2 teaspoons salt, and 1/2 teaspoons pepper in a large bowl to blend. Add broccoli rabe mixture, bread, and 1/2 cup Parmesan; toss to combine.
Transfer to a 1-1/2-qt. baking dish. Top with pancetta and remaining 2 tablespoons parmesan. Bake pudding until puffed, browned in spots, and set in the center, 45-55 minutes.