Preheat oven to 175 degrees C (340 F).

In a bowl, use a fork to break 2 bananas into smaller chunks, set aside.

In another big bowl, add the other 2 bananas, coarsely chopped, add sugar, and mix with a mixer for about 5 minutes, until everything is blended smoothly.

Add melted butter, eggs and vanilla extract, mix with mixer for another 5 minutes.

Add flour, salt and baking soda, using spatula to mix until flour is fully incorporated.

Fold in pecans and stir several times.

Add the smashed bananas from step 2, slightly mix everything.

Grease a loaf pan with butter. Pour the batter into loaf pan, and bake for around 1 hour 5 minutes. Rotate the bread halfway through the cooking period, to make sure both sides are evenly baked. The bread is ready when the surface turns golden brown, and a chopstick inserted into the bread comes clean.

Let the bread cool for 10 to 15 minutes, then move it onto a cooling rack to cool completely before slicing.