Prepare the spread: in a small bowl, mix the mayonnaise with yogurt or sour cream if using, lemon juice, garlic powder, a pinch of salt and pepper. Set aside. This will be the creamy, bright layer that ties the sandwich together.

Heat a grill pan or skillet over medium-high heat. Brush the chicken breasts lightly with olive oil and season with salt and pepper. If you like a little kick, add a few drops of hot sauce or a pinch of paprika on the chicken.

Grill the chicken about 5–6 minutes per side, until it’s cooked through and has nice grill marks. Remove and let rest for a couple of minutes, then slice into thick strips.

Meanwhile, cook the bacon in a skillet until crisp. Transfer to a paper towel–lined plate to drain.

Toast the bread slices until golden and lightly crisp. If you like, you can brush one side of each slice with a tiny amount of the olive oil you used for the chicken.

Assemble the sandwiches: on a slice of toast, spread a layer of the prepared mayo-yogurt spread. Top with lettuce, a couple of slices of tomato, and a few avocado slices. Add a layer of grilled chicken. If using, place a slice of cheddar on top of the chicken and let it melt slightly from the heat. Layer with bacon strips and a few more avocado slices. Finish with another spoonful of spread on a second slice of toast and place it on top.

Repeat for the remaining sandwiches. Slice diagonally and serve immediately for the best texture and flavor.

If you’d like to keep things lighter, swap the bread for a sturdy tortilla and roll it up for a California-inspired wrap.