Caesar Salad Tostadas with White Anchovies and Garlicky White Beans - Rick Bayless

Ingredients

• 1 head garlic, cloves broken apart (you’ll need 12 cloves, divided use)
• 2 serrano chiles, stemmed
• 1 1/2 cups cooked white beans with enough cooking liquid to cover, either canned or homemade
• 3/4 cup plus 2 tablespoons good olive oil (divided use)
• Salt
• 27 white anchovies–the ones with the lightly vinegary taste (divided use)
• 3 tablespoons lemon juice
• 1 tablespoon Worcestershire sauce
• 1 egg yolk
• About 1/2 cup grated Parmesan cheese
• Fresh black pepper
• 2 heads Little Gem lettuce, sliced crosswise into 1-inch ribbons
• 8 four-inch tostadas
• 1 lemon for its zest (optional)