Remove 4 strips orange zest with a vegetable peeler. Squeeze the orange and strain the juice.
Melt the butter with the sugar, orange zest and vanilla bean paste in a large skillet over medium heat. Cook, stirring, until the sugar caramelizes, about 5 minutes. Remove from the heat and stir in the liqueur, orange juice and a pinch of salt.
Return the skillet to medium heat, add the bananas, cut-side down, and cook until glazed and golden, 1 to 2 minutes. Remove from the heat and divide among bowls.
Add the rum to the pan and return to medium heat. Bring the liquid to a boil without stirring, then reduce the heat to a simmer. Cook until the sauce thickens slightly, about 4 minutes. Spoon the sauce over the bananas. Garnish with whipped cream if using and the glazed orange zest.