Preheat oven to 350 degrees. Mash bananas in a bowl and set aside.
Mix flour, baking soda, salt in a bowl and set aside.Cream butter and brown sugar until completely mixed together.
To the creamed butter mixture add the eggs, mashed bananas, yogurt, cinnamon and vanilla extract. Blend completely.
Mix the dry ingredients into the wet ingredients a little at a time. Blend thoroughly but don’t over mix. Scrape down the sides of mixing bowl if using a stand mixer so there are no lumps of flour left.
Pour into a well-greased loaf pan. Bake on the lowest rack in your oven for 55-60 minutes. When it’s done you should be able to insert a toothpick and it will come out clean. If the top is getting too burnt and the inside is not done, cover it with aluminum foil and bake another five minutes.
Let cool before cutting with a serrated bread knife.