1. Start by mixing the mayonnaise, Dijon mustard (if using), and minced garlic in a small bowl. This will be your flavorful spread that ties everything together.
2. Lightly toast the bread slices in a skillet or toaster until golden brown but still soft enough to bend without breaking.
3. Spread a generous layer of the mayo-garlic mixture on one side of each toasted bread slice. This adds moisture and a subtle zing that complements the richness of the avocado.
4. Layer the cooked chicken evenly over two of the bread slices. Sprinkle a little salt and pepper over the chicken for extra seasoning—remember, seasoning is key!
5. Top the chicken with avocado slices, carefully fanning them out so each bite has creamy goodness.
6. Place a slice of cheese on top of the avocado. This is where the magic happens—the cheese will melt and bind all the flavors.
7. Optional: Add a handful of baby spinach or arugula for a fresh, peppery crunch.
8. Close the sandwiches with the remaining bread slices, mayo side down.
9. Heat a skillet over medium heat and add olive oil or butter. Place the sandwiches in the skillet and cook for 3-4 minutes on each side, pressing down gently with a spatula. The bread should be golden and crispy, and the cheese should be melted beautifully.
10. Once done, remove from heat and let the sandwich rest for a minute before slicing. This helps everything settle and makes for easier eating.

I remember the first time I pressed the sandwich down in the skillet and smelled that toasty, buttery aroma wafting through the kitchen—it instantly reminded me of Sunday mornings with my grandmother, when the simplest smells meant love was being served. It’s these moments that make cooking feel less like a chore and more like a cherished ritual.