Place the cashews in a food processor and pulse until finely chopped. Pour in 1/2 cup of the stock and pulse until well combined. Place this mixture and the remaining 1/2 cup of stock, garlic, ginger, soy sauce and chili flakes in a medium pot and bring to a simmer over medium heat. Simmer until a lightly thickened sauce forms, about 3 to 4 minutes. If too thick, thin the sauce with a little more stock. Season with salt and serve warm or at room temperature.