Heat oil in a heavy 3 quart pot over medium heat. Add onions and cook until soft, about 5 minutes. Add garlic, spices and salt and let cook, stirring constantly, for about 1 minute. Add teff and cook, stirring constantly for 2 minutes. Add vegetable broth and bring to a simmer. Reduce heat to low and simmer until teff is soft, about 30 minutes.