For the Ice Cream:

1. Combine the half-and-half, ¼ cup of the sugar, vanilla, salt, and zest in a saucepan. Bring to a simmer and stir until the sugar is dissolved. Remove from heat.
2. Meanwhile, beat the egg yolks and remaining ¼ cup of sugar in a bowl until pale and frothy. Very slowly, add the warm half-and-half mixture to the egg mixture, whisking constantly.
3. Once everything is incorporated, return the mixture to the saucepan and cook over medium-low heat, stirring CONSTANTLY, until the custard is thickened enough to coat the back of a spoon. This will take anywhere between 5-10 minutes. Don’t rush it – you don’t want to cook this too quickly or at too high a heat or you’ll scramble the eggs.
4. Remove the custard from the heat and pour it through a fine-mesh strainer into a large bowl. If using the food coloring to amp up the orange hue, stir in a drop or two now. This is totally optional.
5. Cover the bowl with a piece of plastic wrap, pressing the plastic down into the bowl to gently touch the surface of the custard. This will prevent it from forming a skin on top.
6. Cool the custard to room temperature and then chill in the fridge for at least 1 hour. I often will make the custard the night before and chill it overnight.
7. Transfer the chilled custard to an ice cream maker and freeze according to the machine instructions.
8. Transfer the churned ice cream to an airtight container and freeze for at least 2 hours before serving.

For the Hot Fudge Sauce:

1. Combine all the ingredients except the liqueur in a small saucepan.
2. Bring to a boil and cook for 5 minutes, stirring frequently. Remove from heat and stir in liqueur.
3. Carefully pour mixture into a blender and blend for 2 minutes, venting the top of your blender every so often so the heat doesn’t build up too much.
4. Serve the ice cream topped with the warm fudge sauce.
5. If using at a later time, gently reheat the fudge sauce by microwaving in 15-second increments, stirring after each round, until smooth and melted. It will keep in an airtight container (like a mason jar) in the fridge for several weeks.