Brown the almonds: In a small pan, melt the tablespoon of butter over medium heat. Add in the almond breadcrumbs or almond flour. Cook, stirring well, for a couple of minutes. Turn off the heat and set aside to cool.

Cook the bacon: Preheat your oven to 375°F (190°C). In your cast iron skillet, cook the bacon over medium heat until crispy. Once cooked, remove the bacon. Reserve the bacon fat in the skillet.

Sauté Brussels sprouts: In the same skillet with the bacon fat, add the Brussels sprouts. Cook them on medium heat until they start to brown and soften (about 5 minutes), stirring occasionally.

Add shallots and garlic: Add the chopped shallots and minced garlic to the skillet with the Brussels sprouts. Cook for another 2-3 minutes until the shallots are translucent. They do not need to be cooked through as they will go into the oven. If the mixture looks dry, add some olive oil.

Deglaze with cream: Pour the heavy cream into the skillet. Stir to combine and allow it to simmer for a few minutes. The cream will start to thicken slightly. Turn off the heat on the stovetop.

Add cheese and bacon: Add half of the cheddar and Gruyère cheese into the skillet, along with the crumbled bacon. Stir until the cheese starts to melt and mix well with the Brussels sprouts. Season with salt, black pepper, and optional spices. Layer the remaining cheese on top.

Bake: Place the cast iron skillet in the preheated oven. Cook for 7-8 minutes. Remove from the oven and add the almond breadcrumb topping. Continue to bake until golden brown (approximately 7-8 minutes more). If you want, turn on the broiler to brown the melty cheese.

Serve: Remove from the oven and let it cool for a few minutes before serving.