Combine the granulated sugar with the melted, slightly cooled margarine in a mixing bowl. Stir thoroughly until the ingredients form a uniform, cohesive mixture.
Add the egg and vanilla extract, then continue mixing until the consistency becomes smooth, creamy, and evenly blended.
Introduce the all-purpose flour gradually into the wet ingredients.
Using a spatula, gently fold in the flour until a firm, compact dough develops. Continue folding until no visible pockets of dry flour remain.
Preheat the oven to 180°C (350°F).
Lightly flour a clean work surface and transfer the dough onto it. Dust the top of the dough with a small additional amount of flour.
Knead the dough by hand until it stops adhering to the work surface. Using a rolling pin, roll the dough out evenly on the floured surface.
Cut the rolled dough into desired shapes with cookie cutters.
Arrange the shaped pieces carefully on a baking tray lined with parchment paper, leaving a little room between each cookie to promote even baking.
Place the tray in the preheated oven and bake for approximately 10–12 minutes, or until the cookies are just beginning to develop a golden color.
Monitor them closely toward the end of the baking period to prevent excessive browning.
Remove the baked cookies from the oven and transfer them to a wire rack. Allow them to cool completely.
Once fully cooled, coat or generously dust the cookies with powdered sugar before serving.