Mix all the ingredients together to make the marinade.
Add the beef and let it marinate for 15 minutes in the refrigerator.
In a skillet, heat a drizzle of oil in a pan.
Brown the meat on each side and remove it, keeping it warm in aluminum foil.
Brown the shallot, zucchini and carrot in the same skillet.
Pour in the marinade and return the meat for 2 minutes.
Add the mushrooms at the last moment, just to soften them.
Serve on rice and lemongrass leaves.