Million Dollar Broccoli Casserole

Preheat oven to 400°F. Cook chopped bacon in a large skillet over medium heat, stirring occasionally, until crispy, 8 to 10 minutes. Transfer the bacon to a paper towel–lined plate. Transfer 1 tablespoon of the drippings to a small bowl; discard the remaining drippings. Add ½ cup panko to the drippings in the bowl; stir to combine. Do not wipe the skillet clean.

Meanwhile, place broccoli pieces in a large microwave-safe bowl. Cover and microwave on High until tender-crisp, 6 to 8 minutes, stirring halfway through. Drain and transfer to a 9-by-13-inch baking dish.

Heat 2 tablespoons sun-dried tomato oil in the skillet over medium heat. Add ½ cup sun-dried tomatoes, the minced shallot and garlic and 1 teaspoon Italian seasoning; cook, stirring constantly, until fragrant, 1 to 2 minutes. Add 3 tablespoons flour; cook, stirring constantly, until lightly toasted, 1 to 2 minutes. Gradually whisk in 1½ cups half-and-half and 1½ cups broth. Bring to a gentle simmer over medium heat; cook, stirring and scraping up any browned bits, until thickened, about 2 minutes. Remove from heat and whisk in the softened cream cheese, ¾ cup Parmesan and 1 teaspoon mustard until smooth. Add the sauce to the broccoli in the baking dish; stir to coat. Spread in an even layer and sprinkle with the reserved panko mixture.

Bake until bubbling and golden brown, 12 to 15 minutes. Let stand for 10 minutes, then sprinkle with ⅛ teaspoon salt and the reserved bacon. Garnish with parsley, if desired.