Wisk the milk, eggs, and vanilla together in a medium size mixing bowl.
Next add in the sourdough starter, flour, sugar, baking powder, salt, and cinnamon.
Place your oil in a heavy bottom pan, at least 2 inches deep. Heat the oil to 350-375 degrees Fahrenheit.
Using a funnel or glass liquid measuring cup pour 1 cup of batter into the hot oil carefully back and forth in a crisscross motion and a bit circular.
Fry for 30-60 seconds or until golden brown and then flip and repeat on the other side.
Remove the funnel cake from the hot oil and place it on a paper towel to catch any extra oil. Then, serve immediately with your favorite toppings.
Store them in an air-tight container or baggie at room temperature or in the refrigerator. If they get soggy, you can reheat them in the oven to get back some crispness.
The most popular topping is a dusting of powdered sugar, but you can also add chocolate, a combo of butter, sugar and cinnamon, custard, ice cream, whipped topping, etc.