Grease a 6-quart slow cooker (or larger) and line the bottom with parchment paper for easy removal.

In a large mixing bowl, whisk together the melted butter, granulated sugar, brown sugar, and vanilla extract until combined.

Add the eggs and whisk until just combined. Do not overmix.

Stir in the mashed bananas and sour cream until well blended.

In a separate bowl, whisk together the flour, baking soda, and salt.

Gradually add the dry ingredients to the wet mixture, stirring only until just combined. A few streaks of flour are okay.

In a small bowl, toss the diced strawberries with 1 tablespoon of flour (from the measured amount). Gently fold the strawberries into the batter.

Pour the batter into the prepared slow cooker. Sprinkle the top with optional coarse turbinado sugar if desired. Cover and cook on LOW for 3-4 hours or HIGH for 1.5-2 hours, or until a toothpick inserted in the center comes out clean or with moist crumbs.

Carefully remove the bread from the slow cooker using the parchment paper. Let it cool for 10-15 minutes on a wire rack before slicing. Serve warm.