Heat the oil to 350 degrees, or over medium heat in a large cast iron post.

Pull apart each biscuit.

Fry 2-3 donuts at a time, turning over halfway through and drain on paper towels.

Melt the dulce de leche on 30 second intervals in the microwave.

Pierce each donut with a knife and using a pastry bag or squeeze bottle, fill each donut.

In a dish, combine the powdered sugar and cinnamon sugar and roll each donut in it.

Serve immediately.