This isn’t just any beef stew, however. This stew is fancy. It’s luxe and lush and so intensely flavored, if you’re anything like me, after one bite you’ll forget every crock pot attempt that yielded thin broths, tough meat, weak flavor and, always, unevenly cooked vegetables (potato mush and still-rubbery carrots, sigh), or at least I did. It will an excellent consolation prize for a winter you’re totally ready to be done with, pretty as it can occasionally be.
Place salt pork in a Dutch oven or a large heavy kettle over low heat, and cook until fat is rendered. Remove solid pieces with a slotted spoon, and save for another use, like your salad, vegetables or, uh, snacking. Raise heat to medium-low, and add onion and shallots. Cook until softened but not browned, about 10 to 15 minutes. Use a slotted spoon to transfer to a large bowl.
If necessary, add 2 tablespoons butter to the pan to augment fat. Dust beef cubes with flour, and season lightly with salt and more generously with pepper. Shake off excess flour, and place half the cubes in the pan. Cook over medium-high heat until well browned, almost crusty, on all sides, then transfer to a bowl with onions. Repeat with remaining beef.
Add Cognac to the empty pan, and cook, stirring, until the bottom is deglazed and any crusted-on bits come loose. Add stock, smooth Dijon mustard and 1 tablespoon coarse or Pommery mustard. Whisk to blend, then return meat and onion mixture to pan. Lower heat, cover pan partway, and simmer gently until meat is very tender, about 1 1/4 hours.
Add carrots, and continue simmering for 40 minutes, or until slices are tender. As they cook, heat 2 tablespoons butter in medium skillet over medium-high heat, and sauté mushrooms until browned and tender. Stir mushrooms into stew along with remaining mustard and red wine. Simmer 5 minutes, then taste, and adjust seasoning. Serve hot.