In a sauce pan over medium high heat, add the Oil, allow to get hot. Add Onion, Celery, and Mushrooms, lightly season with Salt, Pepper, and Garlic Plus. Saute for 10 minutes, stirring occasionally. Make a well in centre of pan, add Garlic, saute for 30 seconds, mix well.
Add Thyme, Salt, Pepper, Nutmeg, Worcestershire, Mustard, Sriracha, and Chili, saute 2 minutes. Mix Flour with Chicken Stock, mix well to combine.
Add Wine to the Onion mixture allow Wine to mostly reduce, (about 2 minutes). Add the Chicken Stock mixture to the Onions mix well until combined. Bring to a simmer, reduce heat to medium, simmer for 2 minutes until Sauce thickens, stir frequently.
Add Milk, Tuna, Cheese, Pasta, and Peas, mix well.
Pour the Tuna casserole into a 33 x 25 cm baking dish.
Combine the Breadcrumbs, Parmesan, and Butter. Stir until combined and the mixture resembles wet sand. Sprinkle this over the Casserole and bake uncovered for 20 minutes.
You can place the casserole under the broiler at least 6 inches away to brown and crisp up the topping. Let the casserole sit for 10 minutes before serving. Enjoy!