Remove oil from wok, leaving 1 tbsp. Add butter and shallots. Stir-fry over high heat till shallots turn translucent. Add garlic and stir-fry till lightly golden. Lower heat. Add black peppercorns. Stir-fry till fragrant. Add wine. Stir through. Increase heat to high. Add crab, light soya sauce, dark soya sauce, salt and ¼ cup water. Stir to mix well.
15 g butter, 4 shallots finely minced, 4 cloves garlic finely minced, 1-2 tbsp black peppercorns coarsely ground, 2 tbsp Shaoxing wine, 2 tbsp light soya sauce, 2 tsp dark soya sauce, ½ tsp salt, ¼ cup water, 1 tbsp corn oil