Preheat the oven to 325 degrees F (163 degrees C).
Heat up the heavy cream so that it’s hot but not boiling. You can eyeball it by seeing if smoke is wafting off your cream.
After heating up your cream, whisk together the sugar and egg yolks in a small bowl. Make sure you have a smooth consistency.
The next step is called tempering. Basically, you want to raise the temperature of your egg yolks, so they don't cook when you combine the cream and eggs. To do this, add 1/4 cup of cream to the egg mixture. Whisk well until everything is well incorporated. Then pour the egg mixture into the hot cream. Stir together until all the ingredients are mixed well and the sugar has melted.
Add the vanilla extract and espresso powder and stir. Remove from the heat.
Add 4 ramekins to a baking dish. I used 4 8oz ramekins in a 9×9 baking dish. Ladle the custard over a fine mesh sieve into the ramekins.
Pour 2 cups of hot water into the baking dish to create a water bath for the custard. This helps control the temperature of the custard, so it doesn't overcook.
Bake for 35-40 minutes. Take out the creme brûlée at 35 minutes to check if it's cooked through. To check if they’re done, shake them a bit, and if they move the same way jello moves, they’re done. If they seem a bit loose in the center, bake them for a few more minutes.
Cool for 2 hours at room temperature and then overnight in the fridge.
Add a thin layer of sugar on top and shake off any excess. Use a blow torch to caramelize the sugar and serve.