Preheat oven to 300 degrees F.

Spray a baking sheet with sides, or a baking pan with baking spray and set aside.

In a large saucepan, add sugar and water and heat over medium heat until sugar has melted and you no longer see any sugar granules.

Add peanuts, vanilla, and cinnamon.

Continue to cook, stirring frequently until peanuts are sugar-crusted and no liquid remains on the bottom of the pan when you stir.

Remove from heat and place onto a prepared baking vessel.

Spread peanuts out into as even of a layer as possible.

Place in preheated oven. Bake for 30 minutes, stirring at least once.

Remove from oven and stir to make sure there are no peanuts stuck to the pan.

Set aside to cool.

Once completely cooled, store in airtight containers or baggies.