Preheat oven to 300 degrees F. Start a kettle of water to prep it for boiling. Place six 4 oz ramekins in a baking pan (around 9X13") and set aside. You will add boiling water to the pan right before the custards go in the oven.
Add heavy cream, 3 tablespoons of sugar, and all the spices (cinnamon, ginger, cloves, nutmeg, salt, pepper) to a small saucepan over medium heat. Whisk it over the next 6-7 minutes. You are looking for bubble along the edges of the pan. You do NOT want to bring the cream to a full boil.
Meanwhile, whisk egg yolks, molasses, vanilla, lemon zest, and remaining 2 tablespoons of sugar in a medium bowl. Whisk it until well combined.
After your cream mixture comes to temperature, spoon a ladle of the hot cream into the egg yolk mixture. Make sure you pour it slowly and try to whisk the egg yolks with your other hand at the same time. Whisking is very important to ensure a smooth texture- otherwise you can get clumps of cooked egg! Add another ladleful of cream and continue whisking. Then gradually whisk in the remaining cream mixture.
Evenly divide the custard mixture between the six ramekins in the baking pan. Add boiling water to the baking pan until the water goes about halfway up the sides of the ramekins. Be careful not to add water to the ramekins! Carefully transfer the pan with the ramekins to the oven. Alternatively, you can add the pan with the ramekins to the oven and then pour the water in. This makes transferring slightly less risky!
Bake for 30-35 minutes. You will know they are done when the custard is just set- a little firmer on the edges and still slightly jiggly in the middle. They firm up after cooling.
Carefully remove the ramekins from the hot water right after taking them out of the oven. You can use tongs but if you have a canning tool used for lifting the jars, that works super well here :)
Let them cool for about 30 minutes and then transfer them to the refrigerator to cool for at least 4 hours but ideally overnight.