Spinach Dip Hot Bread

This gooey, cheesy appetizer is one of the most popular dishes at San Francisco's Mr. Digby's, and is perfect for watching the game. The toasty sliced sourdough boule is filled with buttery bechamel sauce and spinach, but the real star is the Calabrian chiles, which lend each bite a gentle kick of heat. Feel free to customize this depending on the bread you have on-hand; it works nicely with a baguette, too.

Ingredient :

  • ¼ cup plus 2 tablespoons unsalted butter, divided

  • 2 tablespoons all-purpose flour

  • ¾ cup whole milk

  • ¾ cup heavy whipping cream

  • 1 ¼ teaspoons kosher salt, divided

  • ¾ teaspoon ground white pepper, divided

  • 1 ½ cups chopped yellow onion (from 1 medium [10-ounce] onion)

  • 1 (10-ounce) package fresh baby spinach (about 8 cups)

  • 14 ounces pre-shredded Parmesan cheese (about 4 1/4 cups)

  • 1 (24-ounce) sourdough boule

  • 1 tablespoon chopped jarred Calabrian chiles

  • 1 ½ ounces pre-shredded low-moisture part-skim mozzarella cheese (about 1/3 cup)

Directions :

  1. Preheat oven to 450°F. Melt 2 tablespoons of the butter in a small saucepan over medium. Add flour, whisking until fully incorporated, about 1 minute. Gradually drizzle in milk and cream, whisking constantly, until fully incorporated and no lumps remain. Bring to a boil over medium, whisking constantly; boil, undisturbed, for 1 minute. Reduce heat to low, and simmer, stirring occasionally, until thickened, about 20 minutes. Stir in 3/4 teaspoon of the salt and 1/4 teaspoon of the white pepper. Remove from heat.

  2. While milk mixture simmers, melt remaining 1/4 cup butter in a large Dutch oven over medium. Stir in onion, and cook, stirring occasionally, until translucent, about 6 minutes. Add spinach, and cook, stirring often, until liquid has evaporated and pot is dry, about 4 minutes.

  3. Pour milk mixture into spinach mixture in Dutch oven; stir to combine. Stir in Parmesan and remaining 1/2 teaspoon each salt and pepper. Remove from heat.

  4. Cut sourdough boule crosswise into 5 (1-inch-thick) slices, cutting through bread almost completely but leaving bottom crust intact. Slice boule lengthwise down center so each slice is halved but bottom crust is intact. Place boule on a large rimmed baking sheet lined with parchment paper or aluminum foil. Spoon spinach-Parmesan mixture evenly between bread slices, and top evenly with Calabrian chiles. Sprinkle evenly with mozzarella.

  5. Bake in preheated oven until top is browned and center is hot and gooey, 7 to 10 minutes.