Mash bananas. Whisk in eggs, sweetener, oil, and vanilla until combined.
Stir wet into dry until just combined. Fold in mix-ins if using.
Pour into prepared pan. Smooth the top.
Bake 50-55 minutes until golden and a toothpick comes out clean. Tent with foil after 35 minutes if browning too fast.
Cool in pan 20 minutes then on a wire rack for at least 1 hour before slicing.
Notes
Store wrapped at room temperature for up to 3 days or refrigerated for up to a week. This bread freezes well for up to 2 months — slice before freezing for easy grab-and-go portions.