Precook bacon. Drain and set aside. In a large slow cooker, add onions, potatoes and 1.5 cup cooked bacon ends. Whisk broth, flour, milk and salt together and pour over onions and potatoes. Cook on low for 6-8 hours and high for 3-4 hours. Just before serving, either bring to a boil in your slow cooker or transfer to a pot on the stove and bring to a boil. Thicken soup with a corn or arrowroot starch slurry if you want a thicker soup. (Whisk starch with about 1 cup water.) Add to boiling soup and whisk until soup has thickened. Top soup with leftover bacon, chives and shredded cheese. For a dairy free option, use a cheese substitute such as Daiya shreds. This soup doesn't freeze well, so make sure you eat it all up or find some friends to share it with!
Notes
I purchase my chopped bacon ends at my local butcher shop. It makes it so quick and easy to prep real bacon bits.