For the Mayonesa Con Chipotle
- 1 egg
- 6 g freshly squeezed lime juice
- 5 g sea salt
- 20 g chipotle in adobo, canned, seeds removed
- 180 ml grapeseed oil
For the Tostadas
- 140 g (about 1) leek, white part only, thoroughly washed and sliced into 3mm-thick rounds
- 60 ml freshly squeezed orange juice from about 2 oranges
- 60 ml soy sauce
- 18 ml lime juice (optional)
- 480 ml rice bran oil, safflower oil, or any vegetable oil with a high smoke point
- 8 day-old corn tortillas
- 340 g sashimi-grade tuna, trout, or other fatty fish, thinly sliced against the grain
- 30 g Mayonesa Con Chipotle
- 1 avocado, cut in half, pitted, peeled, and cut into 8 slices
- Lime wedges, for serving
- Make the Mayonesa Con Chipotle. In a food processor or blender, pulse the egg, lime juice, salt, and chipotle until well combined. With the motor running, slowly add the oil in a thin stream, processing until the mayonnaise emulsifies and turns creamy, about 4 to 5 minutes. Partway through, be sure to turn off the processor and scrape down the sides to incorporate all ingredients. Set aside. (Gabriela encourages you to make your own mayonnaise at home, but you can also start with premade mayo and stir 1 to 2 tablespoons of puréed canned chipotles into it, depending on your spice preference.)
- Prepare the leeks. Place the sliced leeks in a bowl of cold water and use your fingers to gently separate the rings. Transfer the rings to a clean towel and allow them to dry completely.
- Make the tuna marinade. In a small bowl, stir together the freshly squeezed orange juice and soy sauce, and taste. If the mixture isn’t acidic enough, add the juice of 1 to 2 whole limes. The juice should be a little sweet, a little salty, and a little acidic.
- Fry the tortillas. In a large, heavy-bottomed saucepan or Dutch oven, heat the oil over medium-high heat until it reaches 180°C (350°F). Ensure that there are at least 2 inches (5 centimeters) of oil in the pan. Working in batches to avoid overcrowding, add as many tortillas as will fit in the oil, flipping occasionally with a wire skimmer. Cook until golden and firm, about 1 minute. (If your tortillas are thicker, they’ll need more time to fry.)
- Transfer the fried tortillas to a plate lined with paper towels to cool. Repeat the frying process with the remaining tortillas. Once all of the tortillas are fried, don’t discard the oil; you’ll be using it to fry the leeks. Allow the tortillas to cool for at least 15 minutes.
- Marinate the tuna. While the tostadas are cooling, place the fish in a small bowl with the soy sauce–orange juice marinade. Set aside.
- Fry the leeks: Make sure that the oil is at 180°C (350°F). Drop the leeks into the oil and stir constantly so they cook evenly and don’t stick together. The instant you see the leeks turning golden, after about 2 to 3 minutes, remove them with a slotted spoon or wire skimmer and set them on a plate lined with paper towels to cool completely. The leeks will crisp up as they cool.
- Assemble. Once the tostadas are cool, spread a thin layer of mayonnaise evenly across the surface of each one. Distribute the sliced fish among all of the tostadas. Sprinkle each one with fried leeks, and add a slice of avocado. Serve with fresh lime wedges.