In a 6-quart stockpot, heat olive oil over medium heat.
Rinse meat and pat dry. Season with salt and pepper.
Place flanken and onions in pot and sear meat by cooking it over medium heat for 2 to 3 minutes until meat is lightly browned on both sides.
Add remaining ingredients, cover and bring to boil. Skim off any foam that rises to the surface and discard.
Reduce heat to a simmer and cook, uncovered for 3 hours, stirring occasionally. Ladle into bowls and serve.
If refrigerating overnight and reheating, you may have to add 1 to 2 cups of water and mix well to prevent burning.
Recipe Courtesy of QUICK & KOSHER Recipes From The Bride Who Knew Nothing by Jamie Geller (Feldheim 2007) - BUY NOW