Chop the bacon into short thin strips and sautee in a pan over medium heat. When bacon is crisp, remove from pan, and set aside, but leave the rendered fat in the pan. Chop the crimini mushrooms and add them to the skillet. After 6-8 minutes, the mushrooms should be cooked, remove from pan and set aside. In a seperate, dry, skillet over medium heat, add the pearled buckwheat. Toast the buckwheat stirring occasionally to keep it from burning for 2-4 minutes, or until the buckwheat starts smelling toasted. Add 1 cup of stock and 1 cup of water to the pan and bring the pan up to a boil, then reduce the heat to medium and let cook stirring occasionally until most of the liquid is gone. At this point add the other cup of stock and the other cup of water, 4 sprigs of thyme, and 2 bay leaves. When about half the liquid is cooked out, remove bay leaves and thyme. Once the rest of the cooking liquid is almost gone, remove pan from heat, add butter, salt and pepper to taste, add the rest of the thyme (just the leaves this time), and the lemon zest. Also, add the criminis back in. Plate and serve immediately, sprinkling the bacon over the top.