Preheat oven to 375°F.
Heat oil in a skillet over medium-high heat. Add onions, mushrooms and celery; sauté 2 to 3 minutes or until softened. Remove from heat, set aside.
Combine egg, 3 tablespoons chile sauce, soy sauce, garlic powder, black pepper, panko, parsley and sautéed vegetables in a large mixing bowl. Add turkey and mix until well combined; clean hands work best for this.
Place meatloaf mix into an 8-1/2 x 4-inch loaf pan OR mini-loaf pans coated with cooking spray. Drizzle with 2 tablespoons chile sauce. Bake 45 to 50 minutes for large loaf, 20 to 25 minutes for small loaves. Let rest 5 minutes before serving. Serve with cucumber relish.
Cucumber Relish – Combine all ingredients in a mixing bowl; toss well and let sit 3 minutes for flavors to develop.