Next cut up your tomatoes into bite sized pieces. Cut up the lettuce, wash, and spin dry in a salad spinner. Finely dice the onion, or follow my caramelized variation in the recipe card.
Cook the diced bacon over medium heat until the fat renders out and the bacon is crispy. Drain and reserve the bacon grease for another use and set the bacon bits aside.
In the same pan cook the ground beef breaking it up into small bits until cooked through. Drain off any excess grease if needed. Then add the yellow mustard and season to taste with sea salt.