Combine flour, 2 tablespoons sugar, baking powder and salt in a small bowl.
In a medium-sized pot, add water and butter, and bring to a boil until the butter has completely melted. Remove from heat. Quickly add flour mixture with a wooden spoon until it forms a ball. Add vanilla and eggs, one at a time, and combine until the dough is soft.
Add the batter to a piping bag with a large star-shaped tip.
Heat the vegetable oil on medium-high in a deep frying pan. Pipe the churros directly into the oil so they are about 6 inches long and straight. Fry 4-6 churros at a time until they are completely golden. Remove from oil and place on a plate lined with paper towels to remove excess oil. Repeat the process until you have used the remaining batter.
Use a wooden skewer to make a hole on the inside of each churro. Use a piping bag with a long round tip to fill the churros with dulce de leche.
Combine sugar and cinnamon and roll the churros in this mixture.
