Separate the eggs, placing one egg white at a time into a liquid measuring cup and then adding that one egg white to a medium mixing bowl. Add the yolks to a large mixing bowl (or bowl of a stand mixer). There must not be any yolk or shell in your whites. If any yolk gets into your egg whites, you will need to replace the egg whites. (See notes.)
Preheat the oven to 350 degrees F. Grease the bottom and sides of a 9-inch springform pan with cooking spray. (If you need to keep the cake gluten free, do not use baking spray, because it contains flour.)
Place the butter in a microwave-safe bowl. Break the chocolate bars into pieces and add them to the bowl. Cover and heat in the microwave for 25 seconds at a time, stirring as needed, until the chocolate and butter are melted and smooth.
Add the amaretto to the chocolate mixture and stir to combine. Whisk in the almond flour, baking powder and salt and set the chocolate mixture aside.
Beat the egg whites with a hand mixer on low until they're frothy. Add ¼ cup of sugar. Beat on medium-high speed until the egg whites form stiff peaks.
Add 1 cup of sugar to the egg yolks. Use a stand mixer or a handheld mixer with clean beaters to beat the yolks on medium until they're pale yellow. Scrape the bowl as needed.
Use a rubber spatula to stir the chocolate mixture into the egg yolk mixture.
Fold the egg whites into the chocolate batter in three batches, until you no longer see white streaks.
Pour the batter into the greased spingform pan. Smooth the top with your spatula so the batter is even.
Bake for 50-55 minutes. The cake will puff up in the oven and crack.
Let the cake cool in the pan on a wire rack for 15 minutes. The center of the Torta Caprese will sink down to be more even with the rest of the cake.
Before serving, sprinkle confectioners sugar on the cake. Slice into wedges and serve plain or with whipped cream, berries and/or ice cream.
Store the cake covered at room temperature for 3-4 days. The cake freezes beautifully. Wrap it well in plastic, then foil before freezing it. Thaw the cake in the refrigerator for 6-8 hours before serving it.
Have extra eggs on hand in case you mess up when separating the eggs. If any yolk gets into the the egg whites, you won't be able to beat them into stiff peaks. It helps to place one egg white at a time in a measuring cup before adding it to the bowl. That way, if you get yolk in that egg white, you just need to replace that egg white, instead of all of them.
If you need to keep the cake gluten free, do not use baking spray to grease the pan, because baking spray contains flour. Use cooking spray or butter instead.
If you don't have amaretto, you could try another liqueur such as Chambord (raspberry flavored), Grand Marnier (orange flavored) or Strega. We tested this with rum, but the flavor was better with amaretto.
Don't overbake. Torta Caprese should be exceptionally moist on the inside.
Torta Caprese is delicious plain, with a dusting of powdered sugar, but we love it with whipped cream. A scoop of vanilla ice cream would be fabulous too.