The day before:

Season your short ribs with an even coating of flaky kosher salt. Place them in a large ziploc bag and refrigerate them for 24 hours. 

The day of:

Remove the short ribs from the refrigerator and allow them to come down to room temperature for at least an hour before cooking. Season them again with kosher salt and freshly ground black pepper.

1. Preheat oven to 300 degrees F.
2. Heat 2 tablespoons of vegetable oil in a large 6 quart dutch oven over medium-high heat. When the oil is heated (you’ll see light whisps of smoke), sear the short ribs on each side until browned. You may have to do this in batches, so please don’t overcrowd the dutch oven, otherwise they’ll steam instead of brown. Browning can take up to 15 minutes, depending on how many short ribs you have. Transfer browned short ribs to a plate, and set to the side. 
3. Carefully drain all of the fat left in the bottom of the dutch oven to a heat-proof glass. You should have a good amount of browned bits stuck to the bottom, do not scrape that off. Place the dutch oven back over the heat, but reduce it to medium. Add 2 tablespoons of olive oil plus 2 tablespoons of butter, and scrape up the browned bits using a wooden spoon or rubber spatula. When the butter is melted, add the quartered Cremini mushrooms. Season with a generous amount of flaky kosher salt and black pepper. Add the crushed red pepper flakes and herbs de provence. Toss to coat, making sure all mushrooms are coated in fat. Try to arrange them in an even layer if possible, and leave them alone so they can release their liquid and brown. This will take about 6 to 8 minutes or so. First, you’ll see a lot of liquid come out, then it will evaporate and the browning process will begin. Once the liquid is evaporated, toss the mushrooms around so they can brown on all sides, about 5-8 minutes longer. When the mushrooms have developed a nice golden brown color on all sides, add the onion and celery. Season with more flaky kosher salt, and toss to combine. Sauté everything until the onions have softened slightly, about 3 to 5 minutes. Add in the minced anchovy filet, and sliced garlic. Cook for another 2 minutes, then pour in 3/4 cup of the marsala wine. Immediately scrape up any browned bits at the bottom of the pan and allow the marsala wine to cook down for about a minute or two.
4. Nestle in the rosemary and thyme bundle. Lay the short ribs on top of the mushrooms and aromatics.  
5. Pour in the quart plus 1 cup of beef stock (or water). Add the dried mushroom powder, garlic powder, onion powder, cayenne pepper, freshly grated nutmeg, Worcestershire sauce, and dark soy sauce. Stir everything until smooth. Give it a taste and adjust seasoning as necessary. Bring the mixture to a boil. When it starts to boil, cover and place the dutch oven in the preheated oven for 3 hours. 
6. After 3 hours, remove from the oven and place the covered dutch oven on your stove for about 10 minutes. You want to allow the steam to soften any browned bits that accumulated on the sides of the dutch oven so you can easily scrape all that flavor back into the dish. 
7. Meanwhile, increase the oven temperature to 450 degrees F. 
8. Pile the medley of mushrooms in an even layer on a large baking sheet. Drizzle generously with olive oil, flaky kosher salt, black pepper, and a light drizzle of Worcestershire sauce. Toss to combine and arrange in an even layer. Roast for 20-25 minutes or until mushrooms are golden brown.
9. While the mushrooms are roasting, remove the lid from the dutch oven and scrape all that flavor down from the sides of the pot into the dish. Transfer the short ribs to a plate. They should be extremely tender, and the bones should slide out without force. Skim the excess fat off the top of the braising liquid. Try to get as much of it as you can, but don’t worry if some is left behind. Reduce the braising liquid by bringing to a simmer over medium-high heat. Let it reduce for about 8-10 minutes, then pour in the heavy cream and remaining 1/4 cup of marsala wine. Reduce heat to low. Add the short ribs and all accumulated juices back in and let them simmer in the creamy marsala braising liquid for an additional 10 minutes. Give it a taste and adjust seasoning as necessary.
10. Serve the short ribs in bowls, and garnish with the roasted mushroom medley, parsley, and chives. 
11. Enjoy.