Preheat the oven to 400?F. Line a baking sheet with parchment paper.
Place each pork tenderloin between 2 pieces of plastic wrap. With a meat mallet, lightly pound out the pork tenderloin till about 1/8 inch thick. Unwrap and season both sides with salt and pepper. Lay 3 slices of the bacon on a flat surface. Place a pork tenderloin on top of the bacon along one end. Spread 1/4 cup of the duxelles over the top of each pork tenderloin. Lay 4 slices of the avocado on top of the duxelles. Gently roll up each tenderloin with the bacon.
Place the roulades, seam side down, on the prepared baking sheet, and roast until the bacon is brown and crisp and the pork meat is tender, about 30 minutes. Remove from the oven and let rest for 5 minutes before slicing. With a sharp knife, trim the ends of each roulade and cut each across into 4 slices. Cover with aluminum foil to keep warm.
Meanwhile, in a medium-size saucepan, fry the chopped bacon until crispy, about 8 minutes. Add the shallots, garlic, and Armagnac and cook for 1 minute. Stir in the reduction and sugar, season with salt and pepper, bring to a boil, and reduce the heat to a simmer. Cook, stirring, for 5 minutes. Whisk in the butter and remove from the heat. Serve the polenta with the roulades.
Yield: 4 servings