1. Preheat oven to 200°C/400℉
2. Roll out some puff pastry, store bought is absolutely fine
3. Get a shallow pie tin or quiche pan (I tend to use 9.5" ones but any size is fine) and use it as a template to cut out a round of pastry
4. Rub unsalted butter liberally all over the interior of the pan (salted should also be fine but omit the salt in Step 6)
5. Sprinkle the inside of the pan liberally with brown sugar - I prefer Muscavado but this tart was just made with regular dark brown sugar which made it slightly lighter
6. Optional Step: sprinkle some salt on the sugar (I use a couple of pinches of Maldon or Kosher salt for a 9.5" pan.) Alternatively some dark rum would be nice here. Or maybe some dark chocolate chips (although I've never tried that)
7. Slice 2 or 3 bananas about 3cm/1" thick and then layer the slices in concentric circles starting from the outside, get as fancy with the layout as you'd like
8. Lay the disc of pastry on top and then tuck down the edges inside the pan
9. Bake for about 20-25 minutes or until the crust is browned and the caramel is bubbly
10. Remove from oven, hold a plate inverted over the top and flip over