Preheat the oven to 180C/ 350F.
Heat an ovenproof skillet over medium heat and add the butter and bay leaves. Allow to melt and start to bubble. Add the sugar and maple syrup and stir to dissolve. Cook this for a minute or so until the sugar and butter are bubbling. Add the cinnamon and vanilla and cook for a few more seconds. Turn off the heat and remove the bay leaves. If you are using a cake tin, decant the caramel into the bottom of the tin.
Place the plums cut side down around the caramel and then drape the puff pastry over the plums tucking in any edges.
Bake for 25 minutes and until the pastry is golden brown.
Remove and carefully flip the plum tart tartin out onto a serving plate. Serve warm or at room temperature with vanilla ice cream.
