Cook the bacon in a large, heavy pot or Dutch oven over medium heat, until browned and slightly crispy, about 5 minutes. thinly slice the onions and add to pot along with salt, cayenne, black pepper, sugar, and bay leaves. Cook, stirring, until the onions are soft, about 5 minutes. Add the cabbage and stir to mix well. Cook, stirring, until cabbage just begins to wilt or soften, 3-4 minutes. Reduce the heat to medium-low and add the beer. Stir to mix. Cover and simmer, stirring occasionally, for 1 hour. Remove the bay leaves. Remove from heat and serve warm.