Grease a 9x5x2.5 inch pan and preheat the oven to 350F.
Cream the butter and cream cheese in a medium mixing bowl. Gradually mix in the sugar, beating well to combine.
Add the eggs one at a time, beating well after each egg.
In a large mixing bowl, whisk the flour, baking soda, baking powder, and salt.
Gradually stir in the flour mixture into the wet mixture until just combined.
Add the vanilla, mashed banana and mashed strawberries and mix until just combined. Be careful not to over mix.
Pour into the prepared loaf pan (or several loaf pans if using a smaller size) and bake for 1 hour, shielding with tin foil the last 15 minutes to prevent over-browning.