Cut the beef into bite-sized pieces then season with the pepper and salt.
2 ½ lbs. beef chuck roast, 1 tablespoon pepper, 1 teaspoon salt
Heat the avocado oil in a large pot over high heat. Working in batches, add the beef in a single layer. Fry until golden brown then flip the pieces over and fry on the other side. Repeat until all the beef is well browned. (see notes)
1 tablespoon avocado oil
Add the browned beef and beef stock to your slow cooker and set it to cook on low heat for 8-10 hours.
7 cups beef stock
30 minutes before you are ready to eat, add the green beans, celery, mushrooms, zucchini, swiss chard stems, carrots, and garlic to the slow cooker and stir. Season to taste with additional salt, if needed.
1 cup EACH: chopped green beans, celery, mushrooms, zucchini, swiss chard stems, and carrots, 4 cloves garlic
Just before serving, add the swiss chard leaves to the pot and let them wilt.
1 cup chopped Swiss chard leaves
Notes
If you're short on time, you can skip browning the beef and add it straight into your crockpot. The flavor won't be as rich, but it will still taste delicious.Tip: If you want to avoid any last-minute prep, cut the veggies while you sear the beef and store them in a covered container in your fridge. Half an hour before dinner, take them out of your fridge and put them in your crockpot.