Beef Stroganoff

Cut the meat into centimeter-thick slices, trim off any remaining fat, and then cut it into thin strips, half to one centimeter thick. Mix them with two large pinches of salt, a little pepper, and set aside for now.

Peel the onion, halve it, and cut it into half-moons. Trim the dried, tougher end of the stem from the mushrooms, quickly rinse them to remove any substrate residue, and then cut them into quarters or halves depending on their size. Squeeze the juice from the lemon into a bowl, add about 100 ml of cold water, and dip the cut mushrooms in this water on all sides. This will prevent them from browning when cut and later from turning gray in the pan. After a while, drain them again; after all, they are mushrooms and thus absorb a lot.

In a pan, heat the butter until it foams, or simply heat the oil. Add the drained mushrooms and, over medium heat, first let them release their liquid, then evaporate the liquid, and add the onion. Sauté both together, stirring occasionally, until golden brown. Then remove and set aside.