Preheat the oven to 175 degrees Celsius (350 degrees Fahrenheit)
In a bowl combine all of the ingredients for the meatballs. Using your hands work the ingredients together until they are well combined.
Roll the mixture into balls approximately the size of a golf ball (4cm in diameter) and place the rolled meatballs on a parchment paper lined baking sheet. The recipe should make approximately 25 meatballs.
Bake the meatballs in the oven for approximately 25 minutes, flipping them half way through cooking to ensure they brown evenly.
While the meatballs are cooking prepare the sauce. Heat the oil in a pot and cook the onion and garlic for 3 to 4 minutes until the onion becomes translucent. Add in the tomatoes, beef stock and cumin.
If using dried ancho chili, let them soak for about 5 minutes in boiling water and then transfer to a blender along with a splash of the soaking water and blend into a puree.
Add 1 tbsp of the blended ancho chili paste or chiptole paste to the sauce and let simmer for 30 minutes until the liquid has reduced and the sauce has thickened. Taste the sauce and adjust the flavour by adding more chili paste or cumin if desired.
Serve the meatballs coated in the sauce and sprinkled with fresh cilantro. Enjoy!