Kasha can be simmered in a liquid or baked. It is better if cooked in a stock rather than in just plain water. You can mix it, once cooked, with other grains.
Bring 2 cups (8 oz / 250 ml) of stock to a boil. Add 1 cup (4 oz / 120g) of kasha, bring back to a boil, then reduce to a simmer, cover and cook for 15 minutes. When done, the Kasha will be soft and will have absorbed all the liquid.
Kasha is also often coated in egg first before cooking, so that the grains will stay separate instead of clumping together, and there are sometimes that you will want this effect. Take 1 beaten egg, or egg white, and stir the 1 cup of kasha in till all the grains are coated. Turn out into a frying pan heated with a knob or two of butter or a splash of oil, and sauté for 3 to 5 minutes. Then add the two cups of boiling water to this, and proceed as above.
Very tasting as part of poultry stuffing.
Other cooked grains. If you have buckwheat groats, you can make them into kasha by toasting them in a frying pan with oil until they turn a reddy-brown.
1/2 cup, dry, uncooked = 2 oz / 60 g
1/2 cup, cooked = 3 oz / 85g