In a small bowl combine the brown sugar, 3 tablespoons maple syrup, cinnamon, vanilla, and ¼ teaspoon of salt.
Toss the pecans with the sugar mixture.
Lay the pecans out on the prepared sheet pan and bake for 15 minutes, stirring halfway. Cool for 10 minutes.
In a small bowl, make the dressing by combining the olive oil, balsamic vinegar, remaining maple syrup, Dijon mustard, garlic clove, remaining salt, and pepper. Set aside.
In a large bowl combine lettuces, cucumber, tomatoes, red onion, basil, and parsley.
Toss salad with the dressing.
When the pecans have cooled, break them apart if some have clustered together.
Add the avocado, pecans, and optional feta cheese to the salad and serve.