Heat a pot of water to boiling, and add brussels sprouts. Cook for 6 minutes, until tender. Drain and run under cold water. Set aside. 

Heat 12 inch skillet to medium heat. Add bacon, and stir, cooking to release fat. As bacon starts to brown, add onion and prunes, stirring to coat with bacon fat. Cook for 6-7 minutes, until onion is softened. Remove from pan and set aside. 

Cut brussels sprouts in half, or quarters, depending on how big they are. Heat olive oil in same pan, and add brussels sprouts, cut side down, when hot. Sprinkle with salt. Cook for 5 minutes on medium-high heat, then flip over. 

Add bacon prune mixture, and stir to combine. Cook for another 3 minutes, then stir in black pepper, white vinegar, and maple syrup. 

Top with crushed walnuts and serve.