01 -
Place sliced onions, butter, balsamic glaze, Herbes de Provence, salt, and pepper into the slow cooker. Stir to coat onions evenly.
02 -
Cover and cook on high for 6-7 hours or low for 10-12 hours, stirring occasionally, until onions are deep golden and caramelized.
03 -
Once onions are caramelized, add beef and chicken broth, and stir to combine.
04 -
Cover and cook for an additional 30-60 minutes on high to allow flavors to meld.
05 -
Top with Parmesan cheese crisps as desired and serve hot.