Set oven to 300 degrees Fahrenheit, then line muffin pans with 16 liners or grease 16 muffin cups if placing batter directly in the muffin pans.
Combine the dry ingredients (2 cups flour, 1tsp. baking soda, 2tsps. baking powder, ¼tsp. salt, ¼tsp. cinnamon, and ¼tsp. nutmeg) in a bowl. Mix well and set aside.
In another mixing bowl, use a hand mixer or whisk to mix ½ cup melted butter, 2tbsps. oil, and ½ cup sugar. Add in mashed bananas and 2 eggs and continue mixing. Once incorporated, mix in the 1tbsp. mixed essence or vanilla extract.
Add the dry ingredients to the wet ingredients and mix until the batter is smooth. Do not overmix. If using, add dried fruits at this point. Use a tablespoon to transfer batter to one muffin cup at a time. Once the batter is in the muffin cups, gently tap the pans on the table or countertop to release any trapped air bubbles.
Set pans in the middle of the oven and bake for 18 minutes. At 15 minutes in, turn off the oven. You can check muffins but do not remove them from the oven unless you are certain that they are fully ready, otherwise they will drop. Allow the muffins to sit in the oven for an additional 2 to 3 minutes. You can use a toothpick or similar to check the muffins. I usually keep the oven door slightly ajar so the heat escapes rather slowly.
Remove muffins from the oven when the time is up. Allow to cool completely and enjoy!