Preheat your oven to 375°F (190°C). Grease the baking dish with butter and set aside.

In a skillet over medium heat, cook the bacon until crisp. Remove and set aside on a paper towel to drain.

In a medium saucepan, melt 4 tablespoons of butter over medium heat. Whisk in the flour and cook for 1-2 minutes, until lightly golden and bubbling.

Gradually whisk in the milk and heavy cream, stirring constantly until smooth. Bring to a simmer and cook for about 2 minutes until the sauce thickens.

Stir in the roasted garlic, thyme, rosemary, and season with bayou city seasonings, salt, and pepper add more or less if desired. Remove from heat.

Add Half of each cheese and stir until combined and slightly thickened.

Arrange a layer of potato slices in the bottom of the prepared baking dish. Top with a layer of thinly sliced onions, crumbled bacon, combine all the remaining cheese and add the mixture of parmesan, gouda, and cheddar cheeses over the potatoes.

Pour the béchamel sauce over the first layer, ensuring even coverage. Repeat the layering process with the remaining potatoes, onions, bacon, and cheese, then top with the remaining béchamel sauce.

Cover the dish with aluminum foil and bake for 45 minutes. Remove the foil and bake for an additional 25-30 minutes, until the top is golden and bubbly, and the potatoes are tender when pierced with a fork.

Let the scalloped potatoes rest for 10 minutes before serving. Garnish with chives, fresh thyme, or rosemary if desired.