Place a large dutch oven or heavy bottomed pot over medium heat.
In a large plastic bag, combine the flour, pepper, salt, and garlic powder. Mix well.
Add the pieces of stewing beef to the bag of flour and shake well, coating the beef pieces with the seasoned flour.
Add 1 Tbsp of oil to the dutch oven. Add half of the beef pieces and sear the beef on all sides. This should only take a minute or two. Remove the beef from the dutch oven and set aside. Add the last of the oil and sear the remainder of the beef. Remove this second batch of beef and set it aside, as with the first batch. Lower the heat to medium.
Chop the celery, carrots, and onions to approximately the same size.
Chop the turnip and potatoes into slightly larger pieces, about 1 inch square.
Add celery, carrots, and onions to the dutch oven. Cook and stir for 5-10 minutes, until the vegetables begin to soften.
Add the tomato paste. Stir the tomato paste into the vegetables.
Add the potatoes, turnip, broth, rosemary, and bay leaf to the pot. Add enough water just to cover the vegetables.
Bring everything to a boil, then lower the heat to medium-low, keeping a low simmer. Simmer covered for an hour, then uncovered for 1-2 more hours.
Remove the bay leaf from the pot. Add the frozen peas and salt and pepper to taste. Continue to simmer for 10 more minutes, until the peas have warmed through.