Prepare the Vinaigrette: In a small bowl, combine ¼ cup olive oil, fresh lemon juice, honey, poppy seeds, and Dijon mustard. Whisk vigorously until the dressing is smooth and emulsified. Season with a pinch of black pepper. Divide the vinaigrette evenly among six small, leak-proof containers and set aside.
Toast the Pecans: Place the pecan halves in a dry skillet over medium heat. Toast for 3–5 minutes, tossing frequently, until they are fragrant and lightly browned. Immediately remove from the skillet and set aside on a plate to cool completely. Once cooled, give them a rough chop.
Season the Chicken: Pat the chicken breasts dry with a paper towel. In a small bowl, mix together the salt-free Italian herb blend, garlic powder, and ½ teaspoon of black pepper. Season the chicken evenly on all sides.
Cook the Chicken: Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Carefully place the seasoned chicken in the hot pan. Cook for 6–8 minutes per side, until a golden-brown crust forms and the chicken is cooked through. The internal temperature should reach 165°F (74°C).
Rest and Slice: Transfer the cooked chicken to a cutting board and let it rest for 10 minutes. This step is crucial for keeping the chicken juicy. After resting, slice the chicken into thin strips.
Assemble the Jars: Layer the ingredients in six large (32 oz / 1 L) wide-mouth jars for optimal freshness. Start with the sliced chicken at the bottom, followed by the chopped pecans, quartered strawberries, and crumbled goat cheese. Gently pack the baby spinach on top, filling the rest of the jar.
Store for Meal Prep: Seal the jars tightly. Refrigerate the salad jars and the separate dressing containers for up to 4 days. When ready to eat, simply pour the dressing into the jar, seal the lid, shake well, and enjoy.