Sadza: Boil 3 cups of water. In a medium pot, make a paste using some cold water (1 cup). Add the hot water slowly while stirring to avoid lumps.
On medium-high heat, stir with a wooden spoon until mixture thickens like porridge.
Add the rest of corn-meal, mixing in quickly to avoid any lumps. Stir the sadza until it thickens to required consistency.
Oxtail: Season with salt and pepper.
Drizzle the Worcestershire sauce all over the oxtails. Sprinkle flour to coat.
In a skillet, pour olive oil over a medium-high heat.
Once the oil is hot, add oxtails and brown them. Remove the oxtails and put them in a slow cooker. Add the onions, garlic, & tomatoes.
In the same skillet, add the remaining flour and cook stirring continuously until it turns brown.
Slowly pour in the beef broth. Whisk while you pour. Taste and adjust the sauce.
Pour the sauce in the slow cooker. Cook for 6-8 hrs..
Adjust season with salt and pepper, garlic powder, chill powder.