Preheat oven to 350°F (175°C). Line a baking sheet with parchment paper.
In a bowl, whisk together flour, ginger, cinnamon, cloves, baking soda, and salt.
In another bowl, beat butter and brown sugar until fluffy. Add egg and molasses, mix well.
Gradually add dry ingredients to wet ingredients, alternating with hot water. Mix until smooth.
Drop batter by tablespoonfuls onto prepared baking sheet. Bake for 10 minutes or until set.
Cool on baking sheet for 5 minutes, then transfer to a wire rack to cool completely.
For the filling, beat butter until creamy. Gradually add powdered sugar, vanilla, and milk. Beat until fluffy.
Spread filling on the flat side of one cookie, then top with another cookie. Repeat with remaining cookies.