Tostadas with Shredded Beef (Salpicón)

Ingredients:

• 1 boneless beef brisket weighing 1 kg.
• 1 large white onion, cut into 4 pieces
• 3/4 cup olive oil
• 6 tablespoons distilled white vinegar
• 1/4 cup freshly squeezed lime juice
• 1/4 cup chopped red onion
• 2 tablespoons crumbled dried Mexican oregano
• 1 cup chopped, seeded cucumber (half an English or hothouse cucumber)
• 1 cup chopped tomato, seeded (2 pcs.)
• 0.5 cups capers, dried
• 1/4 cup chopped fresh cilantro
• 4 radishes, finely chopped
• 12 corn tortillas
• 2 avocados, halved, peeled, pitted and thinly sliced, for serving

Preparation:

1. Place the brisket in a large pot and add enough water to cover the meat by 2 cm (0.7 in). Add the onion quarters and 1/4 cup salt. Bring to a boil. Reduce heat to medium and simmer, covered, until the brisket is very tender, 2.5 hours. Add more water if necessary to keep the meat submerged. Turn off the heat and let the beef cool in the broth to room temperature. Drain and cool the meat completely.
2. Meanwhile, prepare the vinaigrette by whisking the olive oil and vinegar in a medium bowl. Add the lime juice, red onion, and oregano and whisk again. Season the dressing with salt and pepper to taste.
3. Shred the brisket in a large bowl. Add the cucumbers, tomatoes, capers, cilantro, and radishes and toss to combine. Add the vinaigrette and toss to coat. Season with salt and pepper again if needed.
4. Make tostadas:
   
   Heat a grill pan over medium-high heat. Place a corn tortilla in the hot pan and cook until crisp and golden brown, about 5 minutes per side. Arrange the beef salad on the grilled tostadas and top with a few slices of avocado.