Heat the oil in a deep saucepan or steep-sided stir-fry pan. Add the onions and sauté over medium heat until golden.
Add the kasha and stir in to coat with the oil in the pan. continue to sauté, stirring often, until the kasha is nicely toasted and the onions lightly browned here and there, about 7 minutes.
Pour in the broth or water with bouillon cubes and bring to a slow boil.
Stir in the mushrooms, then lower the heat and simmer uncovered until the liquid is absorbed, about 15 minutes. Stir gently only once during this time, as you don’t want the kasha to get mushy.
Remove from the heat, and season with salt and pepper. Stir in the dill or parsley (or both), and serve at once. Pass along extra fresh herbs for topping individual portions.