Ladyfingers (Savoiardi):

Separate 5 eggs into yolks and whites. Let them come to room temperature.

Preheat your oven to 350 F and line 2 large baking sheets (13" x 18") with parchment paper. On one side of each piece of parchment paper, use a sharpie and a ruler to draw lines marking 4 rows that are 3 inches tall. So that each baking sheet will have four 3-inch tall rows. Flip the parchment paper over so the side with the sharpie marks faces down, and away from the cookies.

In a large mixing bowl, add in 5 egg yolks, 5 tbsp granulated sugar, 1/4 tsp salt, 1 tsp of vanilla extract, and 1 tsp of orange zest, until it looks pale yellow, and the sugar has mostly dissolved, about 3 to 5 minutes. A slight ribbon should fall from the beaters when lifted from the bowl.

Sift in 1 1/4 cup of cake flour into the egg-yolk mixture, but do not fold it in. Just set aside.

Add 5 room temperature egg whites and 1/2 tsp cream of tartar into a glass or stainless-steel mixing bowl, and beat them with an electric beater till it's frothy. Then increase the speed to medium, and very slowly add in 5 tbsp of granulated sugar. When all the sugar has been added, increase speed to high, and keep beating till it forms stiff glossy peaks. You should not feel any more grains of sugar with your fingers.

One-third at a time, gently fold in the egg-white meringue into the egg-yolk / flour mixture. Stop when they are just combined, and be careful not to deflate the egg whites. It's okay to undermix a bit, and stop even if you see a few streaks of white and yellow.

Transfer this mixture into a piping bag fitted with a round tip that is 3/4 inches in diameter. We just used our piping bag with no metal tip. At a 45 degree angle, use the prepared lines on the parchment paper as a guide to pipe the batter into cookies that are about 3 inches long, with about 1 to 2 inches between each cookie. Pipe 5 to 6 cookies per row, in the 4 rows, so that you have about 20 to 24 cookies per baking sheet (it may be slightly more or less, depending on how much was piped for each cookie).

Dust the cookies in the 2 baking sheets generously with about 1/4 cup of powdered sugar, and bake the cookies in the preheated oven at 350 F for 10 to 12 minutes, or until they are just lightly golden but not brown. Let them cool on the tray for a minute, then transfer them onto a cooling rack to cool to room temperature. They should feel dry to the touch, but soft and spongy when lightly pressed.

Let them sit uncovered at room temperature overnight, to let them dry out. Dry cookies are needed so they can absorb the coffee and mascarpone filling.

Cream Filling:

Separate 3 eggs into yolks and whites - set aside and let come to room temperature (about 30 minutes). [NOTE: At this point, also prepare 1/2 cup of espresso or strong coffee. While it is still hot, add in 1/4 tsp of orange zest. Let it cool to room temperature.]

Take a large mixing bowl, add 8 oz of mascarpone cheese, and 2 tbsp of dark rum. Beat with an electric mixer until uniform and smooth.

In a medium sized heat-proof bowl (glass or stainless steel), add in 3 room temperature egg yolks and 3 tbsp of sugar, and beat them together with an electric mixer for about 3 minutes, till the sugar has dissolved and it looks pale yellow in color.

Then place this bowl over a saucepan with gently simmering water over medium-low heat (a double-boiler set up). Be sure the simmering water does not touch the bottom of the bowl. With whisk, continue beating the egg yolk-sugar mixture together vigorously for another 3 minutes, till the mixture has thickened slightly. Then take the bowl off the heat.

Pour the thickened egg yolk-sugar mixture into the bowl with mascarpone, and beat this together with an electric mixer just until it is fully combined. Set this aside in the fridge.

In a separate large mixing bowl, add in 3/4 cup heavy cream and 1 tsp of vanilla extract. Beat this together until the heavy cream thickens and starts to form firm peaks. Be careful not to overbeat the heavy cream - or else it will curdle and separate. One third at a time, fold this whipped heavy cream into the mascarpone mixture. Set aside in the fridge.

Place the remaining 3 room temperature egg whites in a stainless steel or glass bowl. Add in 1/4 tsp of cream of tartar, and beat together for 1 minute, until the egg whites are frothy. Increase the speed to medium and slowly add in 3 tbsp of sugar. When all the sugar is added, increase the speed to high and beat until it starts to form firm peaks.

One third at a time, carefully fold the whipped egg whites into the mascarpone/egg yolks/whipped cream mixture. Rest in the fridge till ready to assemble tiramisu.

Assembling the Tiramisu:

By now the espresso (or coffee) mixture prepared earlier should have cooled to room temperature. Add in 1 tbsp of dark rum, mix, and transfer to a shallow bowl.

Line an 8 x 8-inch dish with 2 oversized pieces of plastic wrap - one going left and right, one going up and down. Use a clean dish towel to press into the plastic, so that the plastic is clinging tightly to the bottom and walls of the dish, and there is plenty of plastic overhanging (can also use a 9-inch round cake pan).

Spread half of the mascarpone cream mixture along the bottom of the dish, making sure that it evenly touches all 4 walls of the dish, and smooth it out into an even layer as much as possible.

One at a time, dunk each ladyfinger cookie into the espresso/rum mixture, rotate it in espresso for about 1 to 2 seconds (they are quite porous, and will fall apart if in the liquid for too long), and place them round side down on top of the mascarpone layer, so that they are close to each other and cover the mascarpone layer as much as possible. Do this with half of the ladyfingers (about 20, depending on the size of your cookies) until you've made an even layer of cookies on top of the mascarpone. Break the ladyfingers in half as needed to fill in any gaps. Ensuring that there are ladyfingers throughout the layer will strengthen the structure of the tiramisu, making it easier to slice and lift. Dust 1 tbsp of cocoa powder on top of this first layer of ladyfingers.

Spread the other half of the mascarpone cream mixture over the ladyfingers, and as before, make sure it touches all 4 walls of the dish evenly, and smooth it out into a flat and even layer as much as possible.

Create another layer of cookie with the remaining half of the espresso-dipped ladyfingers. Again, place them round-side down and make sure there are no gaps. This layer will be the base of the tiramisu when we flip the cake the next day. So make the cookies as flat and evenly spread as possible.

Seal it tight with another layer of plastic wrap. Leave this in the fridge overnight (at least 12 hours).

When you're ready to serve it, remove plastic wrap on top, peel away the overhanging plastic to the sides and make sure they are out of the way. Place a flat serving board that's larger than the 8 x 8 dish on top, and then quickly and confidently flip it over. Slowly and carefully lift off your 8 x 8 dish, and peel off the plastic wrap from the sides and top of the tiramisu, to reveal the cake.

Dust the top with 1 tbsp of cocoa powder. Slice squares and enjoy!