Sirloin Stroganoff

Cut the beef into centimeter-thick slices, remove any excess fat, then cut into thin, half to one centimeter strips. Mix with two large pinches of salt, a little pepper, and set aside.

Peel the onion, cut it in half, then slice it into crescent shapes. Trim the ends of the mushroom stems, rinse them quickly, then cut them into quarters or halves depending on their size. Squeeze the lemon juice into a bowl, add about 100 ml of cold water, and toss the mushrooms in it to prevent them from browning. Drain them after a short while.

In a pan, heat the butter (or oil) until it starts to foam. Add the drained mushrooms and sauté them over medium heat until their liquid evaporates, then add the onion. Stir occasionally and fry until golden brown, then remove and set aside.