Makes 1 9-inch (23-cm) cheesecake.
Toffee Topping and Décor
Preheat the oven to 300ºF (150ºC). Lightly grease a 9-inch (23 cm) springform pan.
For the crust, cream the butter and brown sugar by hand in a mixing bowl. Add the flour, cornstarch and salt and stir until combined but still crumbly. Press this into the bottom of the prepared pan using floured fingers to prevent sticking, if needed. Bake for about 30 minutes, until evenly browned. Cool completely before filling and keep the oven at 300ºF (150ºC). Wrap the pan in foil and place this in a roasting pan with sides.
For the cheesecake, stir the brown sugar and butter together in a sauté pan over medium-high heat until it begins to bubble. Add the lemon juice and cinnamon and simmer, stirring continuously, until the sugar liquefies. Add the bananas and stir to coat and once the sauce returns to a simmer, removing the pan from the heat to cool for a moment.
Beat the cream cheese with electric beaters or in a stand mixer fitted with the paddle attachment on medium-high speed until smooth. While mixing, gradually pour in the granulated sugar, scraping the bowl often. Add the whipping cream, corn starch and vanilla and beat in. Add the eggs one at a time on low speed, being sure that each are fully blended in, scraping down the bowl before adding the next. Stir in the toffee bits by hand.
Now that the banana mixture has cooled a little (but it does not need to cool to room temperature) purée this until smooth and fold it into the cheesecake batter. Pour the batter over the cooled crust, and fill the roasting pan with boiling water so that it comes up halfway up the sides of the pan (but not higher than the foil) and bake for about 50 minutes, until the cheesecake jiggles just in the centre. Turn off the oven and open the door, leaving the cheesecake to sit 20 minutes and then remove the cheesecake pan to cool on a rack. Within 5 minutes of removing from the oven, run a palette knife around the inside edge of the pan – this loosens the cheesecake to help prevent cracking. Cool the cheesecake completely before chilling for at least 6 hours (or overnight).
Run a palette knife around the inside of the chilled cheesecake pan and remove the outer ring. Transfer the cheesecake to a serving plate.
For the toffee topping, bring the brown sugar, cream, butter and maple syrup up to a full boil in a medium saucepan over high heat while whisking. Continue to boil for about 3 minutes, or until the toffee reaches 229ºF (109ºC) on a candy thermometer. Remove the pot from the heat and whisk in the vanilla and salt. If very fluid, set aside the sauce to cool (or transfer it from the hot pot to a heatproof pitcher) until thick but still pourable (if too thick, it can be reheated). Pour this over the cheesecake from the centre and coax the toffee sauce just a little over the edges, using a palette knife if needed. Let this cool for a few minutes and then chill the cheesecake until ready to serve.
To decorate the cheesecake, arrange a few slices of banana on a baking tray or other ovenproof dish (an inverted cake pan works well) – do not use parchment paper. Sprinkle the bananas generously with sugar and use a kitchen torch to melt and caramelize the sugar. Arrange these on the top of the cheesecake. For an added touch, pipe a little whipped cream on top, near each banana slice.
The cheesecake will keep for 2-3 days, refrigerated (although the caramelized banana slices will brown after a day).