Preheat your oven to 350 F.
Mix together the melted butter, brown sugar, and eggs in a large bowl. Add the water
In a separate bowl, combine the flour with baking powder, baking soda, and salt
Add the flour mixture to the wet ingredients.
Drop by rounded teaspoons onto a lightly greased cookie sheet. A lot of recipes say ungreased, but I find that just a smidge of greasing makes the cookies slide off without getting stuck unless you have a newish nonstick cookie sheet.
Cook 8 minutes (for soft cookies) to 10 minutes (for crispy ones)
Remove from cookie sheet and cool on a wire rack.
Once cool, add your buttercream icing and your decorations, then enjoy!