Step 1

Preheat oven to 400 degrees.

Step 2

Submerge romaine leaves in a large bowl of ice water for 10 minutes. Then thoroughly dry in a salad spinner or colander, and place in a single layer on a paper towel-lined dish cloth. Roll up cloth; refrigerate until lettuce is crisp and completely dry (any water clinging to leaves may cause the dressing to break), at least 2 hours and up to 2 days.

Step 3

Place garlic in a large wooden bowl, add 1/4 teaspoon salt, and mash to a paste with a fork. Transfer half of paste to a rimmed baking sheet; set bowl aside. With the fork, stir butter and 2 tablespoons oil into garlic paste on sheet. Toss with bread cubes to evenly coat. Sprinkle with 1/4 cup cheese, season with salt and pepper, and toss again to evenly coat. Spread into a single layer. Bake, stirring halfway through, until crisp and golden, 12 to 15 minutes. Let cool to room temperature on sheet.

Step 4

Add anchovies to bowl with garlic paste and mash to a paste with a fork. Whisk in lemon juice, Worcestershire, Dijon, and egg yolk. Season with 1/4 teaspoon each salt and pepper. Slowly add remaining 1/3 cup oil in a thin stream, whisking constantly. Add lettuce and toss to evenly coat, then toss with remaining 3/4 cup cheese and croutons. Serve immediately.