Preheat the oven to 350°F (180°C). Line a cupcake pan with paper liners.
Sift the all-purpose flour into a bowl. Add the sugar, baking powder, and salt, and mix the dry ingredients together.
In a separate container, combine the vegetable oil, warm water at 90–110°F (32–43°C), and vanilla extract.
Add the liquid mixture to the dry ingredients a little at a time, mixing until no lumps remain.
Spoon the batter into the liners, or use a piping bag, filling each liner halfway.
Bake for 18–20 minutes, until a toothpick inserted into a cupcake comes out clean.
Leave the cupcakes in the pan for 10 minutes, then transfer them to a wire rack to cool completely.