For ginger oatmeal cookies, preheat the oven to 200 °C.
Dissolve the butter with little heat and let it cool down a bit. Lightly whisk the egg. Mix flour with baking powder, salt, ginger powder and cinnamon in a large baking bowl. Add the remaining ingredients including the melted butter and beaten egg. Mix everything together with a wooden spoon to form a tough dough.
Line a baking sheet with parchment paper. Using a spoon, place small mounds on the baking sheet. Leave enough space between them. Sprinkle with a few oats and some candied ginger if desired.
Bake on the middle rack for 8-10 minutes until lightly golden and let the ginger oatmeal cookies cool.