BEEF: Take the beef out of its packing and use a paper towel to wipe dry all over. Cube the meat, measuring 1-1/2 inches. Season everything with salt and pepper, one tsp apiece. In a large, heavy-bottomed saucepan or skillet,* heat 1 tablespoon of oil over high heat. Don't overcrowd the pan; you'll need to brown the meat in small batches. Add the beef in a single layer. and let to gently sear for four minutes on each side. After removing, proceed cooking the remaining meat, using extra oil as necessary. Move the seared steak to a different bowl and put it away for the time being.
GARLIC & ONION: After the steak is completely seared, take the skillet off of the burner and give it a couple of minutes to cool. Don't clean the pan. Place the pan back on top of the burner, increase the heat to medium-high, and then add the butter. Add the onion and garlic when the butter has melted. Sauté for 3 to 5 minutes, or until golden. As you combine, scrape off all the browned crumbs from the pan's bottom. Scrape all of the contents from this pan into the slow cooker or Instant Pot using a spatula.
COOK: Add 2 tablespoons Dijon, 1½ tablespoons Worcestershire sauce, 1¼ teaspoons dried parsley and paprika, and ¾ teaspoon each of dried oregano, thyme, and onion powder to the saucepan along with the beef stock. After giving it a good stir, add the steak back to the dish along with any liquids. Press as much of the meat underneath the liquid as you can while stirring softly.When using an Instant Pot, shut the cover, cook on high pressure for 35 minutes, then let the pressure naturally drop for 10 minutes (or manually release the remaining pressure after 10 minutes). Cook on low for 8 hours (as advised) or on high for 5 hours (slightly less tender) if you're using a slow cooker. EGG NOODLES: When almost done, cook the egg noodles or make mashed potatoes according to the instructions on the package.
THICKEN: After the meat has finished cooking, remove the cover and give it a stir. Pour 1/3 cup of flour into another basin. Take out half a cup of the liquid (without any meat) from the Instant Pot or slow cooker and combine it with the flour in a bowl. Use a fork to quickly whisk the mixture until it becomes smooth and thick. Transfer the thickened mixture and the heavy cream to the saucepan using a spatula. Add the peas and mix.
ENJOY: If you think it needs more salt, taste and add more beef bouillon. Taste again, and if necessary, add more salt or pepper. If you want a bit more acidity—you won't taste it, but it creates a wonderful balance—add more red wine vinegar. Mix well and serve with mashed potatoes or cooked egg noodles. If desired, garnish with parsley or fresh thyme. Have fun!