Preheat the oven to 425°F.
In a large skillet, melt the stick of butter over medium heat. Add the diced onions and chopped mushrooms, and sauté them until soft and golden brown. Leave the juices and butter in the skillet—this is where all the flavor is.
Add the minced garlic and all of the seasonings—salt, black pepper, parsley, Badia Complete, blackened seasoning, and Old Bay seasoning. Stir to coat the onions and mushrooms in the spices.
Pour in the water and add the hickory smoked tuna. Stir everything together and let it simmer for a few minutes to meld the flavors.
Add the cream cheese to the skillet, stirring it in until it fully melts and combines with the mixture.
Whisk in the heavy cream powder, making sure to break up any clumps. Let the mixture simmer for about 5 minutes, stirring occasionally.
Add in half of the shredded cheddar cheese, stirring until it melts into the dip and becomes smooth and creamy.
Spray a large baking dish with nonstick spray and pour the dip into the dish.
Sprinkle the remaining shredded cheddar cheese on top of the dip.
Bake in the preheated oven for about 30 minutes, or until the cheese on top is golden brown and bubbly.
Once baked, remove the dip from the oven and let it cool for 15-20 minutes. This will help the dip set and hold together better when you serve it.
Serve and enjoy your creamy, smoky, and flavorful dip!