You want chicken drumsticks crispy and brown you use a mixture of oil and butter. That way the fat will become hot but the butter won't burn. And you get a nice crispy coating on the outside.
you don't have dry sherry at home, use saké
you definitely want your drumsticks done (no food poisoning in my house), so prick the thickest part of the thickest drumstick with a thick needle (;-)) then press on the outside so moisture comes out. When the liquid is clear, then the chicken leg is done.
sweet soy sauce is nowadays often gluten-free, but always check the packaging carefully to know for sure!
Chop the shallots
Heat a frying pan (with lid) on the heat and pour in the oil.
Then melt the butter in the pan.
Place the drumsticks in the pan and fry on all sides until golden brown.
Meanwhile, mix the soy sauce, sherry, sugar, lemon juice, ginger, and water.
Pour the marinade with the chicken legs and put the lid on the pan.