Preheat oven to 350 degrees F. In a stand mixer, or hand held, mix together softened butter and sugar until well combined. Then add in eggs and mix well. Next add in vanilla, sour cream and mashed bananas then, while the mixer is on, slowly add the flour, baking soda and salt and mix slowly until completely combined, scraping the sides and the bottom.
Meanwhile, grease your pan(s) and lightly flour so that your bread won't stick. If using one 9x5 loaf pan, bake bread for about one hour. If using two smaller loaf pans, bake bread for about 45 minutes. Enjoy!