Pita Pockets with Crunchy Lettuce, Roasted Beets, Chicken & Manchego Cheese

adapted from thekitchn.com
Makes 8 pockets filled with 1/2 cup salad and 1/4 cup shredded chicken
Ingredients

2 large beets, leaves removed
2 chicken breasts (3/4 to 1 pound total)
1 bay leaf
4 oz crunchy lettuce leaves
1/2 cup finely shredded Manchego cheese
4 whole pita rounds, sliced in half

For the mustard vinaigrette:

1 tablespoon extra-virgin olive oil
1 tablespoon cider vinegar
1 tablespoon brown mustard
Salt and pepper, to taste

Preparation

Heat the oven to 400°F. Scrub the beets clean and pat them dry. Wrap them loosely in foil and roast in the oven until tender all the way through when speared with a fork, 50 to 60 minutes. Remove the beets from the oven and let them cool enough to handle.
Meanwhile, poach the chicken. Place the chicken in a medium-sized pot and cover with 1 inch of water. Add the bay leaf, the smashed garlic, and 1 teaspoon of salt to the pot. Bring the water to a boil over medium-high heat. Once boiling, reduce the heat to low, cover, and let the chicken simmer. Cook until the chicken is opaque through the middle and an instant-read thermometer in the thickest part of the meat registers 165°F, 8 to 12 minutes, depending on the thickness of the chicken. Remove the chicken from the water and let it cool on a clean plate.
To make the salad filling, chop the lettuce into thin shreds and transfer to a mixing bowl. Rub the peels off the beets with a paper towel. Slice the beets into cubes, and then transfer them to the bowl with the lettuce. Whisk together the vinaigrette ingredients and pour over the lettuce and beets. Toss to combine. Add the shredded Manchego and toss to combine. Taste a bite of salad and add salt and pepper if you'd like. At this point, the salad mix can be refrigerated for up to 5 days. (Note: The lettuce will wilt a bit over time, but will still retain some crunch.)
When the chicken has cooled, pull it into shreds with your fingers or two forks. Store the chicken separately from the salad filling; the chicken can be kept refrigerated for up to 5 days.
To assemble the pita pockets, carefully open each pita half and fill with 1/2 cup of salad filling and 1/4 cup of shredded chicken. If it will be longer than 4 hours before you eat your pita pockets, wrap them well and store them in the refrigerator.