Prepare waffles ahead of time per waffle maker directions (or while bacon in step #2 cooks). Cool on wire racks.
Place the bacon on a lined sheet pan and roast in a 400-degree oven for 15-20 mins or until crisp.
Slice tomatoes and wash lettuce, set aside.
In a small bowl, make maple-mustard sauce by stirring the three ingredients together. Add salt and pepper to taste. Add more mustard or maple depending on your preference.
Blot bacon. Once bacon and waffles are cooled, prep the sandwiches: Slather one waffle with sauce, layer with arugula, tomatoes and bacon. Sprinkle with salt and pepper as you like. Top with another waffle. Slice in half and enjoy!