How to Make It
Make the vinaigrette: Puree passata, vinegar, piquillos, anchovies, garlic, and sugar in a blender until smooth, about 15 seconds. With blender running, slowly drizzle oil into blender to emulsify. Season to taste with salt and pepper.
Make the croutons: Heat oil in a medium-size heavy skillet over medium. Add garlic; cook, stirring constantly, until fragrant, about 30 seconds. Discard garlic. Add bread cubes; cook, stirring often, until golden brown, about 8 minutes. Transfer croutons to a paper towel–lined plate and season with salt; set aside.
Make the salad: Toss radicchio, endive, escarole, and 2 tablespoons oil in a bowl; season with salt and pepper. Spread 3/4 cup vinaigrette on a platter. Pile salad leaves on top; spoon vinaigrette over salad, if desired. Arrange ham around salad; top with croutons. Drizzle with remaining 1 teaspoon oil. Garnish with hard-boiled eggs, if desired.