Over medium-high heat, heat a deep skillet with about 2 inches of vegetable oil to 375°F.

While the oil is heating up, add 1 cup of water, the butter, brown sugar, and salt to a large saucepan and bring to a boil. Remove from the heat and quickly stir in the flour until the mixture forms into a ball (it'll take about 1 minute).

In a separate bowl, whisk together the eggs and vanilla, then add to the flour mixture, stirring until well combined. The dough should be sticky.

Combine the granulated sugar and cinnamon on a plate.

Put the dough into a decorating tube or pastry bag fitted with a large star tip. Check that the oil is ready, then squeeze the dough into the oil, starting from the outside of the pan and spiraling in.

Fry until golden brown all over, about 2 minutes on each side. Using a slotted spoon or long wooden chopsticks, remove the churros from the oil and place on a large plate lined with paper towels to absorb the grease. While the churros are still warm, roll them over the cinnamon-sugar mixture until well coated. Repeat until all the dough is used. Cut the churros into 4k-inch-long pieces, being careful not to burn yourself.

Enjoy them immediately.

NOTE: To test your oil without a kitchen thermometer, place a dollop of the dough into the oil. When the oil is hot enough, the dough will begin to bubble up right away.