• If using regular carrots, cut into large chunks of even size. Otherwise, use baby carrots.  If using medium sized potatoes, cut them in even halves so that they cook evenly (or use baby potatoes).
  
• In a large frying pan, heat the avocado oil until it shimmers.
• Pat the beef dry, and generously season with kosher salt and pepper.
  
• Sear the beef on both sides, until golden brown (about 10 minutes per side). Remove the beef and set into a slow cooker (I line mine with Reynolds slow cooker liners for easy clean up.)
  
• Nestle the carrots and potatoes along side the beef.
  
• In the same pan, add the sliced onion and stir scraping up the brown fond from the beef, until softened.  Add the pepper flakes and garlic.  Set on top of the beef in the slow cooker.
  
• In the same pan, add the beef broth, balsamic vinegar, brown sugar, Worcestershire sauce and soy sauce and stir until combined.
  
• Pour the sauce evenly over the beef and vegetables. Place the lid on and set on low for 8-10 hours (or set on high for 4-6 hours).
  
• To adapt this for a pressure cooker, saute the beef in the pressure cooker pot and remove. Saute the onions, garlic and red pepper flakes. Add the sauce ingredients, and then place the beef on top. Lock on the lid and pressure cook for about 50 minutes.
  

For the sauce:

• Remove the beef and vegetables. Strain the remaining sauce and place into a sauce pan.  Bring to a simmer, and mix the cornstarch slurry and add to the sauce to thicken.
  
• NOTE: If the sauce has any cornstarch lumps, simply strain.
  
• To serve: Slice the beef against the grain (or shred), serve with vegetables and plenty of balsamic glaze.