With a rolling pin or meat mallet, flatten meat to about 1/4 inch thick.
Spread mustard over meat.
In a large skillet over medium high heat, cook the bacon and onion until bacon's crisp.
Spread the bacon and onion mix over meat. Sprinkle chopped pickle's on top.
Roll up meat and secure with preferably string or turkey pins but if you don't have either of those toothpicks will work just fine.
Place meat roll in skillet over medium high heat in bacon grease and brown on all sides. *if you only had toothpicks to work with, brown as much of the meat as you can
Move meat to a baking dish.
Stir flour with fat in skillet and mix until smooth, slowly stirring in beef broth. Cook over medium heat until thickened, stirring frequently.
Pour the sauce over meat. Cover and bake at 325 degrees for 1 1/2 hours.
Let stand for 10 minutes before slicing. Pour sauce over meat and serve immediately.