Heat a generous splash of olive oil in a large cooking pot over high heat.
Add the meat and sear on all sides until it gets a deep brown color. Let the meat cook for 3-4 minutes on each side before flipping to ensure it creates a nice crust.
Remove the meat from the pot and transfer it to a plate or dish and set aside.
In the same pot add another splash of olive oil and drop the heat to medium-low. Add the onion, leeks, garlic, and mustard seeds and cook until softened.
Pour in the lemon juice and lemon zest. With a wooden spoon scrape the bottom of the pot from the brown bits.
Add meat back to the pot. Add also the bay leaves, thyme, and marjoram. Pour that splash of wine in as well.
Cook for 2-3 minutes for the wine to evaporate completely. Add the carrots and celery. Season with salt and pepper.
Pour in the stock and enough hot water to cover the meat completely. Wait until it starts to boil. Then drop the heat to low and simmer covered for about 1 hour to 1 hour and a half. Prick the meat with a knife to see if it's tender. If not simmer a bit more. Adding a splash of hot water if needed. Once the meat is tender proceed on adding the potatoes.
Add the potatoes and turmeric to the pot. Put the lid back on and simmer until potatoes get cooked as well. Takes about 30 minutes. If there is too much water in the pot then uncover the pot and raise the heat to medium-high. And cook like this until the sauce thickens.
Serve with plenty of fresh ground pepper on top!