Prepare pearl onions (if using). Bring a small saucepan of water to a boil, drop pearl onions, into water for approx. 30 seconds. Remove from saucepan, remove skins, and set aside.
Preheat oven to 350˚ F.
Cook the bacon in large, deep cast iron skillet over medium heat.
Remove bacon from skillet, set aside.
Pour all but 1 tbsp bacon grease from skillet into a heatproof container.
Add Gary's QuickSteak Sirloin Beef to skillet and sauté, add packet of Wow! Seasoning to beef as it cooks. Remove from pan and set aside.
Add chopped celery and garlic to skillet and sauté until celery is softened, being careful not burn the garlic.
Add Guinness and Worcestershire sauce to skillet. Bring to a simmer.
Add seasoned beef back to skillet and stir in chicken broth, tomato paste, bay leaf, and thyme. Bring to a simmer.
Add potatoes, carrots, and prepared onions.
Add 1 tbsp water to cornstarch to make a slurry and pour into simmering beef and vegetable mixture. Stir into cooking stew.
Add sliced mushrooms and simmer an additional 10 minutes uncovered until stew has thickened and mushrooms are cooked through
Add cooked bacon, turn heat to low setting.
Prepare dumplings; in a medium bowl, stir together self-rising flour and garlic powder, cut in shortening until mixture resembles small peas, stir in cheddar cheese, and add milk and stir until dry ingredients are just moistened.
Using a small scoop make small balls with the dough and place them on top of the stew. They will grow as they cook so leave ample room between each dumpling.
Place the stew into preheated oven and bake uncovered until the dumplings are browning and cooked through, approximately 30 to 40 minutes. Garnish stew with sliced onions and chopped parsley if desired.