Cut the chicken into one-inch pieces. Thread one end of the Sweet Potato “Fettuccine” on the skewer, then a piece of chicken, then the other end of sweet potato on the skewer. Next put on a mushroom, then another sweet potato-chicken. Continue threading until all the chicken and mushrooms are threaded.
Mix together the garlic, lemon juice and zest, salt, pepper, olive oil, and rosemary. Let the skewers marinate in the sauce for 15-30 minutes. Grill over medium heat until done, about 5 minutes on each side.
For the mustard sauce:
In a bowl, whisk together the mustard, vinegar, lemon, maple, herb, garlic, and salt. While whisking, slowly add the oil to make a smooth emulsion. Serve with cooked skewers.