Preheat the oven to 425 degrees F (220 degrees C). Grease cookie sheets.

Beat brown sugar and butter together in a large mixing bowl with an electric mixer until light and fluffy; add egg and mix well. Stir in mincemeat.

Sift together flour, salt, and baking soda together; stir into mincemeat mixture.

Drop by teaspoonfuls, about 2 inches apart, on prepared cookie sheets.

Bake in the preheated oven until edges are golden brown, about 7 to 10 minutes.