You can use the blade of a sharp paring knife to test the doneness of a cupcake if you don’t have any toothpicks handy. You can also touch the tops of the cupcakes (carefully- they’re hot) to see if it’s springy or soft. The edges should look done and the tops should no longer be glossy. The cupcakes should also not sink in the middle after removing them from the oven as this is a sign that the centers are unfinished baking.