Preheat your oven to 350 degrees and line a cupcake pan with papers.
Whisk together the soy milk and vinegar and set aside until it curdles.
Sift the flour, cornstarch, baking powder, baking soda and salt into a bowl and mix.
In a separate large bowl, beat together the margarine and sugar for about 2 minutes or until light and fluffy, be careful not to over-beat or the margarine will melt. Beat in orange and vanilla extracts, then alternate between flour mixture and soy ilk mixture, beating until no large lumps remain.
Fill cupcake liners 2/3 full and bake for 20-22 minutes or until tops spring back when lightly touched.