Preheat oven to 350 degrees, Fahrenheit (175 Celsius)
In a large bowl, combine the flour, baking powder, salt, oats and brown sugar.
In a medium bowl, whisk together the oil, egg, buttermilk, vanilla, bananas and melted butter.
Stir the wet ingredients into the dry ingredients, until incorporated. Do not over mix.
Gently fold the strawberries and rhubarb into the batter.
Pour the batter evenly into a prepared 9×5 loaf pan that has been sprayed with baking spray.
Bake in a preheated oven for approximately 90 minutes, or until a toothpick or cake tester inserted into the center comes out clean.
Cool on a wire rack for approximately 20 minutes and then turn the loaf out of the pan to cool completely before slicing and serving.
Notes
Store in covered on the counter for up to 3 days.Store covered in the refrigerator for up to 7 days.May be frozen. Wrap well or store in an airtight freezer container for up to 2 months.