In a saucepan, add chicken breasts, half an onion, four garlic cloves, 2 bay leaves, and liquid (water or broth). 

Bring to a boil, then lower the heat and simmer until the chicken is fully cooked, about 15-20 minutes. 

Peel and grate the carrot into a bowl. Cut the whole onion in half, slice thinly, and place in a small bowl. 

Slice the lettuce thinly and set aside in a small bowl. 

Once the chicken is cooked, remove it from the pot and set it aside in a bowl to cool for 5-8 minutes. 

While the chicken cools, cut the tomatoes into quarters, remove the onion from the broth, and cut off the root. 

In a blender, combine the cut tomatoes, onion, four garlic cloves, chipotle in adobo, and ⅓ cup of the chicken broth. Blend until smooth. 

Strain the sauce through a fine mesh sieve and set it aside. 

Heat a deep sauté pan over medium heat and add about 1 tbsp olive oil. 

Add sliced onions and cook until translucent. Add grated carrots and cook until softened. 

Pour in the strained sauce, stirring occasionally. Cook everything together for about 10 minutes, adding a pinch of truffle salt. 

Shred the cooled chicken and mix it into the sauce. Continue to cook for 5 more minutes, allowing the flavors to meld. 

Heat up the tortillas on a skillet or comal. Place the chicken tinga onto the tortillas. 

Top with Mexican cream or crème fraîche and shredded lettuce. Serve immediately and enjoy!