Make the Homemade Teriyaki Marinade: In a small saucepan, add soy sauce, water, mirin, brown sugar, garlic and ginger. Stir to combine and dissolve sugar. On medium heat, bring marinade to a simmer. In a small bowl, add cornstarch and water, and stir to dissolve cornstarch. While stirring marinade on stovetop, add cornstarch mixture, stirring constantly to avoid lumps. Increase heat to medium-high and cook 1-2 minutes stirring constantly until thickened. Makes 1 cup.

Place pork and teriyaki glaze in a large re-sealable plastic bag. Move bag around to coat the pork. Refrigerate at least 2 hours or overnight. Drain meat and discard marinade. Heat grill to medium-high.

If using bamboo skewers, soak skewers in water for 30 minutes. Using eight 10-inch skewers, start with onions, then peaches, then pork. Grill each skewer approximately 7-9 minutes, turning a couple of times. Pork should be barely pink inside. Place skewers on serving plates, cover with foil and let sit for 5 minutes before serving.