Finely mince the onion. Peel the bell pepper and mince it. Combine the flour with the mustard and onion powder. Boil the beans.
Heat butter and cook the onions. Add the bell pepper, garlic and cook for another 5 minutes.
Add the flour, mustard and onion powder and cook for 2 minutes over low heat. Bit by bit, pour in beef broth.
Use roughly 5 green beans at a time and drag them through the sauce before wrapping the bacon strips around the beans.
Put the bacon and bean bundles on a rack on a baking sheet. Cook in the oven until the bacon is crispy.