3 anchovy fillets, mashed Kosher salt and freshly ground pepper
2 tablespoons fresh lemon juice
2 cups 1/4-inch-diced white bread
1/4 cup freshly grated Parmigiano-Reggiano cheese, plus more for garnish
1/4 cup mayonnaise
1 small garlic clove, smashed
Preheat the oven to 350°. In a medium bowl, toss the bread with 2 tablespoons of the olive oil and season with salt and pepper. Spread the bread on a baking sheet and toast for about 10 minutes, stirring once, until golden and crisp.
Meanwhile, in the same bowl, using a spoon, mash the anchovies to a paste with the garlic and a pinch of salt. Whisk in the mayonnaise, lemon zest and lemon juice, then whisk in the remaining 2 tablespoons of olive oil and season with salt and pepper. Stir in the 1/4 cup of grated cheese.