Tostadas de Tinga — Chipotle-shredded chicken on crisp tortillas

Put the chicken thighs in a medium pot with the quartered onion, garlic, salt, and 1 litre cold water. Bring to a boil, then reduce to a steady simmer. Cook uncovered 25 minutes until the chicken is cooked through. Transfer the chicken to a board; reserve the cooking liquid.

While the chicken cooks, caramelise the sliced onion. Heat the oil in a wide skillet over medium heat. Add the onion and cook, stirring often, 15–18 minutes until deeply golden and sweet. Do not rush this step.

Blend the tomatoes and chipotle chiles until smooth. Pour into the caramelised onion skillet. Add the oregano and cook over medium-high heat, stirring, 8 minutes until the sauce thickens and darkens. Add 120 ml of the chicken poaching liquid and cook 3 minutes more.

Remove the skin and bones from the chicken. Shred the meat into medium strands with two forks or your fingers. Add to the sauce and fold to coat. Taste and adjust salt and chipotle. The tinga should be moist but not soupy.

Spread a thin layer of warm refried beans on each tostada. Pile with tinga, then top with shredded lettuce, a drizzle of crema, crumbled queso, avocado slices, and pickled jalapeño. Serve immediately.