Preheat oven to 400°. Spray an 8-well cast-iron wedge pan with baking spray with flour.
In a small bowl, whisk together flour, baking powder, salt, and cinnamon. In a large bowl, whisk together sugar, egg, sour cream, melted butter, and vanilla until smooth; stir in mashed banana.
Stir flour mixture into sugar mixture until combined; stir in ½ cup strawberries. Divide batter among prepared wells. Press remaining ¼ cup strawberries into batter in wells.
Bake until edges are lightly browned and tops are dry, 20 to 25 minutes. Let cool in pan on a wire rack for 10 minutes. Remove from pan, and let cool completely on a wire rack. Store in an airtight container for up to 3 days.
Notes
KITCHEN TIP: Banana bread batter can be made ahead and refrigerated overnight; stir the chopped strawberries into the batter just before baking.
Recipe by Southern Cast Iron at https://www.southerncastiron.com/strawberry-banana-bread-wedges/