Fire up your Traeger smoker (or any other smoker) to 180-F and place the beef cubes onto a pan (or right onto the grill), season them with salt and pepper, and smoke for about 45 minutes to give them a good smoke flavor.
Meanwhile, saute the onions, celery, and garlic in a skillet with the butter and cooking oil until the onions are translucent; about 8 minutes. Deglaze the skillet with the red wine and let the wine reduce for a minute.
Transfer the smoked beef cubes to a cutting board and cut them into bite-sized pieces.
Place the bite-sized beef cubes, onion-celery-wine mixture, tomato paste, thyme, bay leaves, and Worcestershire sauce in a smoker-safe casserole or cast-iron dish.
Mix the all-purpose flour with 1/2 cup beef broth until it is a smooth paste, then add the remaining beef broth. Whisk this into the beef stew - the flour will thicken the stew as it cooks.
Smoke the beef stew at 350-F or whatever temperature you need to keep the stew simmering. 350-F is a good spot to start. Smoke the stew until the beef is tender (about 40 minutes) then add the diced potatoes, chopped carrot, and pickled onions. Simmer for another 20 minutes or until the vegetables are tender.
Add the frozen peas and heat the stew back to a simmer, adjust the salt and pepper, and serve!