Bring this vegetable-bin staple front and center in this creamy gratin -- you'll be surprised with the results.
Preheat oven to 400 degrees. In a large bowl, mix celery, 1/2 cup Parmesan, cream, 1/2 teaspoon coarse salt, and 1/4 teaspoon ground pepper. Divide evenly among four 6-ounce ramekins, packing mixture in firmly. Place ramekins on baking sheet, and cover tightly with aluminum foil. Bake until celery is tender, 35 to 40 minutes.
Meanwhile, tear bread into large pieces, and pulse in food processor until coarse crumbs form. Add remaining 1/4 cup Parmesan, and drizzle with olive oil; pulse just until crumbs are coated with oil, 4 to 6 times.
Remove aluminum foil from ramekins. Dividing evenly, sprinkle breadcrumb mixture over celery. Return to oven and bake, uncovered, until golden, 8 to 10 minutes more. Let sit 5 minutes before serving.