First Step: Prepare Ingredients and Oven. Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish with cooking spray to prevent sticking. Dice the onion, carrots, and celery, mince garlic, and shred cooked turkey. Measure out noodles and dairy ingredients.

Second Step: Cook the Noodles. Bring a large pot of salted water to a boil. Cook egg noodles until al dente, approximately 6 minutes. Drain and rinse with cold water to stop cooking and prevent sticking. Optionally, cook noodles in chicken or turkey stock to enhance flavor, reserving 1 cup of the cooking liquid for the sauce.

Third Step: Sauté Vegetables. In the same pot or a large skillet, melt butter over medium-high heat. Add diced onion, carrots, celery, salt, and pepper. Sauté for 8–10 minutes until vegetables soften and onions turn translucent. Add minced garlic, cayenne pepper, and dried thyme and sage if using. Cook for an additional minute to release aromas.

Fourth Step: Create the Creamy Sauce. Sprinkle the flour over the sautéed vegetables and stir for 1 minute to eliminate raw flour taste. Slowly whisk in milk and reserved noodle cooking liquid if using. Stir frequently until the sauce thickens and comes to a gentle simmer, about 5–6 minutes. Remove from heat.

Fifth Step: Combine Ingredients. Stir in 3 cups of shredded cheddar cheese until melted and smooth. Fold in shredded turkey, sour cream, and cooked noodles. Add peas and corn or additional vegetables if desired. Taste and adjust seasoning with more salt, pepper, or cayenne as preferred.

Sixth Step: Assemble and Bake. Transfer the mixture to the prepared baking dish and spread evenly. Sprinkle the remaining 1 cup of cheddar cheese evenly over the top. Bake uncovered for about 30 minutes until heated through and the cheese on top is melted and bubbly.

Final Step: Rest and Serve. Remove casserole from the oven and let it rest for 5 minutes before serving. Optionally, serve with hot sauce to add extra flavor and spice.