Preheat oven to 350 °F
Let butter soften at room temperature
Cream butter and sugar together for 5 to 7 minutes
Scrape sides of bowl to ensure ingredients are well combined
Add eggs one at a time
Mix until just incorporated
Add buttermilk, vanilla extract, and mashed bananas
Add flour in increments, mix until just incorporated
Grease loaf pan
Smooth banana bread batter into loaf pan
Bake at 350 °F for approximately 60 minutes, or until a tester inserted in the center comes out clean
Remove from oven and let stand for 10 minutes
Gently remove banana bread from loaf pan and allow to finish cooling on wire rack
Slice and enjoy!