1. Preheat oven to 350°.
2. Heat 1 tablespoon oil in a saucepan over medium heat. Add onion; cook 6 minutes. Add garlic and flour; cook 2 minutes. Gradually add stock, stirring constantly; bring to a boil. Remove from heat; stir in 1/4 teaspoon kosher salt, 1/4 teaspoon pepper, and cream cheese.
3. Cook bacon in a skillet over medium heat. Remove bacon. Add mushrooms to drippings in pan; cook 5 minutes. Add 2 teaspoons canola oil to pan; swirl to coat. Add chopped leek, celery, and carrot; cook 5 minutes, stirring occasionally. Stir in sherry; bring to a boil. Cook 3 minutes or until liquid evaporates. Add leek mixture, chicken, brown and wild rice blend, parsley, 1/2 teaspoon salt, and 1/2 teaspoon black pepper to sauce; toss to combine. Scrape mixture into an 11 x 7-inch baking dish. Toss breadcrumbs with melted butter; sprinkle over casserole. Bake at 350° for 25 minutes.