Bacon makes everything better, especially star chef Lidia Bastianich's sauteed brussels sprouts with walnuts and bacon.
In a large straight-sided skillet, heat the olive oil and crisp the bacon over medium-high heat. Remove the crisp bacon from the pan and set aside. Add the onion to the pan, and cook until almost tender, about 5 minutes.
Add the garlic. Once it is sizzling, add the brussels sprouts and season with the salt and red pepper flakes. Sprinkle with the vinegar, reduce heat to medium, and cook, covered, until golden and tender, about 18 minutes, stirring occasionally. Add a couple of tablespoons of water at any point if it seems they're sticking to the pan.
Add the walnuts and crisp bacon. Cook, stirring just until combined, about 1 minute. Remove garlic and top with grated Grana Padano. Serve.