If using roasted buckwheat groats, transfer them to a fine mesh strainer and rinse under running water until the water runs clear. If the buckwheat grains are not roasted, then pan-roast them in a dry pan on low heat until golden brown.
Transfer the buckwheat to a pot with a glass lid. Add butter, stirring through the buckwheat to cover the grains, then increase heat to high, add boiling water, and continue to stir until the water is on a rolling boil. Once boiling, cover the lid, reduce to medium to low heat, and allow the buckwheat to cook for 20 minutes or until the water has evaporated. Do not remove the lid during this period.
Once the water has evaporated, remove the pot from the heat, and allow the buckwheat to sit for another 10 minutes.
While the buckwheat is cooking, fry the bacon lardons in a fry pan until crunchy, then transfer to a dish; fry the onion on low heat in the bacon fat to slowly caramelise, adding the olive oil and perhaps a little butter if needed, then transfer to a dish; and lastly, fry the mushrooms on high heat in the same bacon-onion juices, again, adding a little more olive oil or butter needed, then set aside while you soft-boil the eggs.
Remove the lid from the cooked buckwheat, fluff with a fork, stir through the salt, pepper, star anise, fish sauce, and half the mushrooms, bacon, and onion, and combine well.
Distribute the cooked buckwheat kasha between two bowls, arrange the remaining half of the mushrooms, bacon, and onion on top of the kasha, along with the halves of soft-boiled eggs, and diced gherkin.
Add a dollop of sour cream to each bowl, garnish with fresh dill, and wash down with black tea and lemon for breakfast or lunch, or shots of vodka if this is dinner.