Heat a griddle or large non-stick pan over medium-low heat. In a large bowl, gently whisk flour, sugar, baking powder, baking soda, and salt.
In a separate medium bowl, mash the banana. Add the buttermilk, butter, egg, and vanilla, and whisk to combine.
Add liquid ingredients to the flour mixture. Using a spatula, stir to combine. Do not overmix. If it looks too thick, add a little more buttermilk (buttermilk thickness can vary). Gently fold in the strawberries or set aside to sprinkle on top of the batter when cooking.
Lightly grease griddle or pan with non-stick spray or a little butter. Place ~¼ cup batter onto the griddle to create pancakes. Sprinkle strawberries on pancakes (if set aside), and gently press down as needed. Cook until tiny bubbles appear on the surface and the edges start to firm up.
Flip and cook ~2 more minutes. You might need to lower the heat as you cook additional batches. Hold in the oven on a warming setting (~170° F) until ready to eat. Enjoy!