Pre-heat oven to 350 degrees and lightly butter a 9x5" metal loaf pan.
In the bowl of an electric mixer or in a large bowl with a hand mixer, beat butter until light and fluffy, 2-3 minutes. Add sugar and beat until well blended.
Beat eggs into mixture one at a time. Add mashed bananas and vanilla extract and mix until combined. Batter may look a bit lumpy.
With the mixer on low speed, beat in pancake mix until just combined, taking care not to over-mix.
Pour into prepared loaf pan and bake for 35-45 minutes, until edges are turning golden and a toothpick inserted into center comes out clean. Turn out onto a rack and cool.