Preheat oven to 150 degrees.

Combine the oats, sugar, cinnamon powder and salt in a bowl. In a smaller bowl, combine the melted butter, honey and vanilla essence well.

Pour into the dry ingredients. Using a spatula, mix well till all the rolled oats is covered.

Spread this mixture on a large baking tray, as thinly as possible.

Bake for a total of 60 minutes.

After every 20 minutes, take out the pan, give it a nice mix inside out, put it back into the oven for another 20 minutes. In between the baking, you will stir the mixture for two times.

Take out the pan and stir the granola till it cools down to room temperature.

Cool completely before storing into a clean air tight container.

Use within 2 weeks.

Notes:

You can replace the butter with oil, but I would prefer butter because it gives it a nice flavor and smell.