Add beef to a medium-sized bowl. Season beef with salt and pepper. Add 1 tablespoon of soy sauce and the minced garlic, stir to combine.
Heat large saute pan over medium-high heat, add 1 tablespoon vegetable oil and 1 teaspoon sesame oil.
Once the oil is very hot, add beef mixture in one single layer. Sear meat on one side for 2 minutes, flip and cook another 2 minutes on other sides. Beef will not be fully cooked.
Add potatoes, onions, carrots and seared beef to a slow cooker.
Add beef stock, oyster sauce and ginger slices. Make sure the meat and vegetables are submerged in the stock. Cover and cook for 3 to 4 hours on High, or 7 to 8 hours on Low.
In a small bowl make the cornstarch slurry by combining ¼ cup of cornstarch and ¼ cup of cold water.
Add it to the slow cooker and stir. Set slow cooker on high and cook another 30 minutes, until sauce is thickened.
Notes
Stovetop directions:
Heat large pot over medium-high heat, add 1 tablespoon vegetable oil and 1 teaspoon sesame oil. Add beef mixture and ginger to the pot, sear meat on all sides. Reduce the heat to medium.
Add 1 tablespoon of oyster sauce to the pan and stir. Add onions to the pot, stir and cook for two minutes. Add the potatoes and carrots to the pot. Add 3 cups of beef stock, covering the meat and vegetables.
Bring a pot to boil then gently simmer until potatoes and carrots are fork tender, about 30 to 45 minutes.
In a small bowl make the cornstarch slurry by combining 1/4 cup cornstarch and 1/4 cup cold water. Increase the heat to medium, allowing the stew to boil gently. Gradually add the slurry, mix the stew and allow the stew to cook and thicken for a few minutes. For a thinner sauce, start by adding half of the slurry, then additional slurry until you reach your desired consistency.