Preheat oven to 350°F. Cook bacon in a large cast-iron skillet over medium heat, turning occasionally, until crispy and rendered, 10 to 12 minutes. Transfer bacon to a paper towel-lined plate to drain. Do not wipe skillet clean. Finely chop bacon.

Add panko to drippings in skillet and cook over medium, stirring occasionally, until golden brown, 3 to 5 minutes. Transfer to a medium bowl; rinse and wipe skillet clean. Stir herbs into breadcrumbs and set aside.

Slice cabbage in half through the root. Cut each half into 4 wedges, keeping root intact. Brush cabbage wedges all over with 2 tablespoons of the olive oil. Sprinkle with 1 teaspoon of the salt, 1 teaspoon of the garlic powder, and ½ teaspoon of the pepper.

Heat 1 tablespoon of the oil in same skillet over medium-high. Add cabbage wedges and cook, undisturbed until browned, about 5 minutes. Flip and continue to cook until browned on second side, about 5 more minutes. Remove from heat. Arrange cabbage wedges, shingling as needed, in a greased 13- x 9-inch baking dish.

Heat remaining 1 tablespoon oil in a medium saucepan over medium. Add onion and cook, stirring occasionally, until just softened, about 4 minutes. Stir in cream, broth, Worcestershire sauce, mustard, and remaining ½ teaspoon salt, ½ teaspoon garlic powder, and ¼ teaspoon pepper; bring to a simmer over medium, about 3 minutes.

Stir together cheese and cornstarch until evenly coated in a medium bowl. Gradually whisk cheese mixture into cream mixture until smooth, about 1 minute. Simmer, whisking often, until sauce coats the back of a spoon, 1 to 2 minutes.

Pour mixture over cabbage wedges; cover with aluminum foil.

Bake in preheated oven until cabbage is almost fork-tender and sauce is slightly thickened, about 40 minutes. Uncover and continue to cook until cabbage is fork-tender and sauce is thickened and bubbling around the edges, 10 to 15 more minutes. Top evenly with bacon and herb panko. Garnish with smoked paprika.