Preheat oven to 400 degrees F (200 degrees C). Line 2 baking sheets with parchment paper.
Combine brown sugar and margarine in a large bowl; beat with an electric mixer until fluffy. Beat in squash and eggs. Add flour, baking powder, vanilla extract, salt, cinnamon, and ginger; mix until dough comes together. Fold in raisins and orange zest.
Drop spoonfuls of dough a few inches apart on the prepared baking sheets.
Bake in the preheated oven until edges are firm and tops are golden, about 15 minutes.