Preheat the oven to 350 and prepare a loaf pan with parchment and grease. Set to the side.
In a large bowl, mash the bananas until they are smooth and mushy. Then, add in the eggs, oil, sugars, sour cream, and vanilla. Use a whisk to mix everything together.
Add in the flour, baking soda, and salt. Mix with the whisk until everything is combined.
Add in the chopped strawberries and rhubarb. Use a whisk or rubber spatula to mix the fruit into the batter thoroughly.
Pour the cake batter into the prepared pan and bake the cake in the oven for 55-60 minutes. It is a dense cake, so it might take longer in the oven. When the cake is done, a toothpick should run clean from the batter.
Let the cake cool fully in the pan on a cooling rack before slicing. When the cake is cool, slice the cake and serve.