Preheat the oven to 180°C. Spread the butter over the backing pan and dust it with a little bit of flour, just to get sides coated. After pan is ready put it in the fridge while preparing the mixture for the pie and until oven is heat up

Mix in the large bowl all of the ingredients, there's no difference in what order. After mixing everything together take out the backing pan from fridge and pour the mixture in

Bake for 40 minutes. After done I like to serve it it with a little bit of sour cream on the side