Cut the beef into cubes, wash the zucchini, cut off the ends then peel and cut the potatoes into relatively large chunks.

Mix the flour with salt and pepper and lightly coat the cubes of beef. Set it aside.

Lightly sauté the potatoes and the zucchini in a pot with a thick bottom then remove them and set them aside.

Sauté the meat well on all sides. When it has browned evenly, add boiling water (careful so that the oil doesn't splatter as you add the water) about 1 l so that it covers the meat (of course, that also depends on the size of the pot) unless you are using a pressure cooker. In that case, use less water.

Add the lemon juice (you can also add a tbsp of Worcestershire sauce if you like), cover the pot and let the meat simmer for 45'.

Add the zucchini and the potatoes. If you like you can add a little more salt and pepper. Let everything simmer until the meat is done (about 45' more).