Homemade walnut, apple, and banana pie

Ingredients:

4 ripe bananas (mashed)
2  small apples  (peeled and diced)
4    large eggs
200 ml   vegetable oil  (or 180 g melted butter)
280 g brown or white sugar
320 g all-purpose flour
1 1/2 teaspoons baking powder
1 teaspoon baking soda
1 1/2 teaspoons ground cinnamon
1/2 teaspoon salt
120 g chopped walnuts
1 teaspoon vanilla extract
Small whole walnuts for garnish

Step-by-step preparation: