Arrange an oven rack in the top third of the oven and preheat to 400°F (200°C).

Cook the sugar and butter in an 8" skillet over medium heat, swirling the skillet often, until the mixture turns deep golden brown, about 8–10 minutes.

Remove from heat and stir in the orange zest and cinnamon.

Pour the caramel mixture into a 7½" x 12" baking dish and spread to cover the bottom.

Lay the banana halves cut side up over the caramel, cutting pieces as needed to fit in the baking dish.

Unfold the puff pastry sheet over the bananas, trimming the edges to fit the dish, and tuck in the edges.

Prick the pastry sheet all over with a fork.

Bake until the pastry is puffed and golden brown and the caramel is bubbling around the edges of the dish, about 30 minutes.

Transfer the baking dish to a rack and let cool for 2 minutes.

To serve, place a serving platter or baking sheet upside down over the baking dish and carefully invert the tart onto the platter or sheet.

Cut the tart into large squares and serve with scoops of vanilla ice cream, if desired.