In a small bowl, mix the lemon juice into the milk and let sit for 5 minutes.
Sift together flour, baking powder, and salt in a medium bowl and set aside.
In another bowl, whisk melted butter, egg, sugar, and vanilla extract until combined.
Combine wet ingredients with dry, then gradually whisk in the milk mixture until batter is thick but scoopable.
Heat a skillet over medium-low heat and spray with cooking spray. Pour batter to form pancakes and cook until bottoms are golden brown.
Flip pancakes and cook other side until golden brown. Repeat with remaining batter.
Slice bananas into 0.5 inch pieces.
In a skillet over medium heat, melt butter. Stir in brown sugar and cinnamon until sugar dissolves and sauce thickens, about 2-3 minutes.
Add banana slices in a single layer and cook 3-4 minutes until golden, then flip to caramelize the other side.
Remove skillet from heat and carefully add rum. Light with a long lighter to flambe if desired, allowing alcohol to burn off and flavor to develop. This step is optional.
Top pancakes with caramelized bananas and sauce, then serve immediately.
Notes
For a non-alcoholic version, omit rum and substitute with extra butter and brown sugar. Perfect for a special weekend brunch.