4. Meanwhile, put ginger, garlic, and remaining 1/4 cup oil into a wok or a large nonstick skillet and heat over high heat. When ginger and garlic start to sizzle, about 30 seconds, give them a stir, then add mushrooms and minced ham. Season to taste with salt and stir-fry for 1 minute. Add soybeans and crab and stir-fry until heated through, about 2 minutes. Stir in tofu and vermouth and let boil for 5-6 minutes. Add stock and boil, stirring occasionally, until tofu dissolves into flecks and thickens the sauce slightly, about 5 minutes. Season to taste with salt, pepper, and cayenne. Mix cornstarch with 1/4 cup water and stir into wok. Return mixture to a boil, stirring as it thickens slightly. Keep stir-fry warm over lowest heat.