Step 1

Break the dark chocolate into small pieces and place them in a microwave-safe bowl.

Step 2

Add 2 teaspoons butter.

Step 3

Microwave in 20-second intervals, stirring after each interval until the chocolate is fully melted and smooth. Set aside to cool slightly.

Step 4

In a cold bowl, whip ½ cup of the heavy whipping cream until it reaches soft peaks. Set it aside in the refrigerator to stay chilled.

Step 5

Carefully separate the 3 large eggs, placing the yolks into a small heatproof glass bowl and the whites into a large, clean mixing bowl. Set aside.

Step 6

Fill a small saucepan with about 1 cup water and bring to a gentle simmer.

Step 7

To the bowl with egg yolks, add 2 tablespoons sugar and 2 tablespoons amaretto liqueur.

Step 8

Place the bowl with yolks over the simmering water (make sure the bowl does not touch the water).

Step 9

Continuously whisk the egg yolk mixture until it becomes pale, fluffy, thickened, and reaches about 160°F (71°C) on an instant-read thermometer. Remove from heat immediately.

Step 10

Gently fold the slightly cooled melted chocolate mixture into the egg yolk mixture. Blend until fully combined and smooth. Set aside.

Step 11

Using clean beaters or a whisk attachment, beat egg whites with a pinch of salt until foamy.

Step 12

Gradually add the remaining 1½ teaspoons sugar, and continue whipping until stiff, glossy peaks form.

Step 13

Add about ½ cup of whipped egg whites into the chocolate mixture to lighten it.

Step 14

Gently fold the chocolate mixture into the remaining egg whites, being careful to keep as much air in the mixture as possible, until thoroughly combined.

Step 15

Carefully fold the chilled whipped cream from Step 2 into the chocolate-egg mixture.

Step 16

Use gentle, sweeping motions, being cautious not to deflate the mousse.

Step 17

Divide the mousse evenly among individual ramekins or serving glasses.

Step 18

Cover each serving with plastic wrap.

Step 19

Refrigerate mousse for at least 4 hours, preferably overnight, until fully set.

Step 20

Just before serving, whip the remaining ¼ cup of heavy whipping cream along with 2 teaspoons amaretto and 1 teaspoon sugar until soft peaks form.

Step 21

Remove the mousse from the refrigerator just before serving.

Step 22

Garnish each mousse with a dollop of amaretto whipped cream, toasted almonds, and chocolate shavings or curls, if desired.