Making the escabeche. Heat 4 tablespoons of the oil in a large (10- to 12-inch), deep skillet over medium-high. Add the onions, garlic and jalapeños; fry stirring often, until onions are crisp-tender but not brown, about 5 minutes. Stir in the broth, vinegar, thyme, cinnamon stick, pepper, bay leaves and cloves. Simmer, covered, over low heat, stirring occasionally, for 30 minutes. Remove from heat, and season with the remaining salt, usually about 3/4 teaspoon.
Finishing the dish. In a large (10-inch) skillet set over medium high, add oil and Brussels sprouts and cook for 5-6 minutes until sprouts are browned on at least one side. Add Brussels sprouts to escabeche mixture, stir to combine and scoop into warm tortillas. Top with cooked bacon and queso añejo.