Toffee Filling:

Place an oven rack in the middle position and preheat your oven to 425 F (220 C). Pour 1 can (14 oz) of sweetened condensed milk into a cake pan and tightly cover the pan with aluminum foil.

Place this cake pan with condensed milk in a large roasting tray, place the roasting dish on the middle rack in your preheated oven, with the roasting dish not pushed all the way in. Do not close the oven door yet. When the roasting dish is in the oven, pour boiling water into the roasting dish so that it goes up about one inch high, creating a water bath for the condensed milk. It's okay if the cake pan floats in the water. Very carefully push the roasting dish further into the oven so it is centered, and close the oven door.

(Pouring the boiling water while the roasting dish is already in the oven will avoid having to carry the heavy dish with boiling water inside it).

Bake in the oven at 425 F (220 C) for 2 hours, until the condensed milk has thickened and caramelized. Transfer the thick toffee mixture into a heat-proof bowl or measuring cup, add in 1/2 tsp of kosher salt, and whisk to get rid of any lumps. Let the toffee cool completely to room temperature. Assembling the pie with warm toffee will result in excess moisture in the pie. Turn the oven temperature down to 350 F (175 C).

Graham Cracker Crust:

The oven rack should be in the middle position and preheated to 350 F (175 C).

Take a medium-sized mixing bowl, add in 2 cups of graham cracker crumbs (18 sheets or 2 sleeves of Nabisco graham crackers), 2 tbsp of dark brown sugar, and 1/2 tsp kosher salt. Mix these together to combine. Then add in 7 tbsp of unsalted butter that has been melted and 1 tsp of vanilla extract. Mix these together until they are well combined.

Take a 9" spring form pan, and lightly butter the bottom and sides of the pan. Transfer the graham cracker mixture into it, and press the mixture into the bottom of the spring form pan and about 1" up the sides. I like to use the bottom of a stainless-steel measuring cup to pack it in just tight enough so they stick together, but not too tight that the resulting crust is too hard.

Bake this crust in the preheated oven at 350 F (175 C) for 10 minutes or until the crust is lightly browned. Let it cool to room temperature on a metal rack.

Assembling the Pie:

When the toffee and graham cracker crust have cooled completely to room temperature, you're ready to assemble the pie. Add a thin layer of toffee to the bottom of the graham cracker crust, just enough to cover the surface with a thin layer, and spread it out evenly.

Cut 4 large firm-ripe bananas into cross-sections about 1/2 an inch thick, and arrange them in the springform pan by pressing them diagonally upright into the toffee in concentric circles, overlapping each other. Tightly pack in as much of the slices from the 4 large bananas as you can, filling in any gaps with smaller bits of banana. You want as much banana in the pie as possible to help cut the extreme sweetness of the toffee.

Add the remaining toffee mixture over the banana, and smooth it out as much as possible, filling in the sides and gaps between the banana slices with toffee, making sure the banana slices are covered with toffee. Let this rest in the fridge while making the whipped cream topping.

Whipped Cream Topping:

In the bowl of your stand mixer, add in 1 1/4 cups of very cold heavy cream, 2 tbsp of powdered sugar, and 1 tsp of vanilla extract. With the whisk attachment, beat this on medium-high speed until you see stiff peaks forming.

Spread the whipped cream evenly over the banana-toffee layer and smoothen the top surface as much as possible with an offset spatula. Let the pie rest in the fridge while working on the chocolate curls.

Chocolate Curls:

Put 2 large sheet pans in the fridge for a minimum of 10 minutes. Set up a double boiler over medium heat. Add in 4 oz of bittersweet chocolate (about 2/3 cup chocolate chips) and stir it around till it's all melted and smooth. Take the bowl off the heat.

Take 1 of the sheet pans out of the fridge, place it upside down on the counter, and pour half of the melted chocolate on it. With a spatula, push the chocolate back and forth, spreading it into a thin layer over both sheet pans. As you push and spread the chocolate back and forth, you'll see it firm up if your room is cold enough / during winter. You are done when the
chocolate changes from being glossy and shiny to having more of a matte look.

Do the same thing with the second sheet pan and the remaining half of the melted chocolate.

During the summer / if your room is warm, it is necessary to put the sheet pans with the thin layer of chocolate in the fridge for 20 minutes for the chocolate to set. Also, put your bench scraper in the freezer, so it's cold when it touches the chocolate.

When you think your chocolate is set enough, take one sheet pan at a time out of the fridge (so the other half of chocolate doesn't warm up while working on the first pan) and your cold bench scraper, and at a 45-degree angle, scrape it with a pretty quick and confident motion. If the chocolate starts to crumble immediately, it means the chocolate is too cold, and let it warm up for 5 to 10 seconds in a warm room / 2 to 3 minutes in a cool room, and try again.

If the chocolate just clumps up into a melted pile onto your scraper, then it means it's not cold / set enough, and needs to go in the fridge for another 10 minutes.

When the chocolate is just the right consistency, with a pretty quick and confident motion, the chocolate will form curls when you scrape it at a 45-degree angle. This step can be very temperamental. And there's only a small window of time (30 second - 1 minute in a warm room / 5 minutes in a cool room) when your chocolate is the right temperature / consistency that it forms curls. So, you might have to put the sheet pan back and forth in the fridge multiple times before you get all the curls you want.

Try your best not to touch the chocolate with your fingers - I handle the chocolate with the bench scraper and a toothpick. With each successful curl, cut the curl off with the bench scraper, and using the bench scraper and a toothpick, lift it onto a parchment paper-lined tray.

Once you've made curls from the first sheet pan, place those curls in the fridge. Then repeat the same thing with the second sheet pan.

Make as many curls as you'd like. I aim for a total of about 40 small curls that are half an inch long. Once you have about 40 small curls you're happy with, store your curls in the fridge (or in the freezer on a very hot day) till you're ready to use them, as the curls may melt and lose their shape.

Arrange your 40 small chocolate curls on the top surface. I'm placing them in circles around the pie, with some curls on top of each other, leaving about 1 inch from the edge of the pie.

Refrigerate the pie for a minimum of 8 hours, preferably overnight, for the layers to set completely. Carefully lift off the sides of the springform pan to reveal the beautiful pie. Serve chilled. Enjoy!