Combine Ingredients: In a medium saucepan, add the rolled oats, water, and cinnamon stick (or ground cinnamon). Bring to a boil over medium heat.
Cook the Oats: Once the mixture starts boiling, reduce the heat to low and let it simmer for 10-12 minutes, stirring occasionally. The oats will soften and absorb the liquid, thickening the mixture.
Add Milk and Sweetener: Once the oats are cooked, add the milk (or coconut milk), sugar, and a pinch of salt. Stir well to combine.
Simmer Further: Let the oatmeal simmer for another 5-7 minutes, stirring occasionally. Add the vanilla extract and condensed milk (optional) for added creaminess and sweetness.
Serve: Once the Avena has reached your desired thickness and consistency, remove it from the heat. Serve warm, and top with optional toppings like sliced banana, raisins, or coconut flakes.