Make the Churros
In a medium bowl, combine the remaining 1 cup of sugar with the cinnamon and cardamom. In a large saucepan, heat 2 inches of vegetable oil to 350°. Working carefully and quickly, pipe about eight 3-inch lengths of batter into the hot oil; use a knife to cut between the pieces. Fry over moderate heat, turning once, until golden and cooked through, 5 to 6 minutes. Using a slotted spoon, lift out the churros and let drain for 10 seconds, then transfer them to the spiced sugar and toss to coat. Transfer the churros to a platter and keep warm. Repeat with the remaining batter and spiced sugar. Serve the churros with the mocha sauce.