Line a loaf pan with plastic wrap, leaving a good amount of overhang on the edges.

Crush fennel seeds with a mortar and pestle. Combine fennel seeds and heavy cream in a sauce pan and heat until the cream just begins to show signs of simmering around the edges. Remove from heat, cover, and let sit for one hour. After an hour, pour the cream through a sieve into a stainless steel bowl. Cover with plastic wrap and refrigerate overnight (ideally), or until cream has chilled completely.

Whip fennel-infused cream to stiff peaks and set aside. Combine egg yolks, sugar, orange juice and zest, and salt in the top of a double boiler. Whisk constantly over simmering water until the mixture has thickened a good deal. Immediately remove from heat and pour into the bowl of a stand mixer. Using the whisk attachment, beat for approximately 6–8 minutes, or until the mixture is light and fluffy and has doubled in volume. Fold whipped cream and chocolate into the mixture, then pour into the loaf pan. Fold plastic wrap over top and freeze until solid (at least 6 hours). Once frozen, unwrap the plastic wrap on top, then invert onto a serving tray (if it doesn’t slide out of the pan right away, give it a few minutes). Unwrap, slice, and serve topped with almond streusel.

To make the streusel: Preheat oven to 350°. Pulse all ingredients in a food processor until crumbly but not too fine. Spread on a baking sheet (it’s best to not spread it too thin, as it can burn easily), crumbling up any still-large bits of butter or almond paste. Bake for 10–12 minutes, or until streusel has just begun to brown around the edges. Let cool, the break it up a bit with your fingers.