In a medium bowl, combine flour, lemon zest, 1/2 teaspoon cinnamon, baking powder, and salt. Set aside.
In medium saucepan, melt butter.
Stir in cream and vanilla extract.
Bring cream to a boil until the edges begin to foam. Remove from heat and cool slightly.
Temper the egg by whisking in 2 tablespoons of warm cream to the egg. Once the temperature of the eggs has risen, add remaining egg to the cream mixture.
Stir the cream mixture into the dry ingredients.
Knead dough on a lightly floured surface.
Form 20, 1-inch balls from the dough.
Using a rolling pin, roll out each ball into a very thin tortilla, about 5-inches in diameter.
Place all tortillas onto a cookie cooling rack. Allow to dry for at least 3 hours or more.
When preparing to fry, mix together 1 cup granulated sugar and 2 tablespoons cinnamon in a shallow pan. Set aside.
Line baking sheets with cooling racks, set near the frying station.
Using a wok, or large saucepan, heat vegetable oil to a temperature of 350°F.
Add one to two bañuelos at a time.
Fry both sides until golden brown.
Gently sprinkle both sides of bañuelos with cinnamon sugar. Set on prepared baking sheets.