04Once the sugar has melted, add in the unsalted butter and swirl the pan from side to side. The caramel will bubble; this is OK. Remove the pan from the heat and use a spatula to help you pour the caramel sauce into your prepared cake pan. Pour the chopped nuts on top of the caramel sauce.
05Add the banana slices to the pan in a radial pattern. Overlap the banana slices with more banana slices in the the areas that look like they have open gaps.
06Roll the pastry dough out into a 9" circle. Carefully place the pastry dough over the banana slices in the pan. Tuck the edges of the dough into the sides of the pan. Transfer the tart to the oven to bake for about 20 to 25 minutes, or until the pastry is golden.
07Immediately after removing from the oven, run a knife along the edges of the pan. Flip the pan upside down onto your serving plate. Scoop any extra sauce and nuts that have stuck to the pan onto the tart.