General tips
Strain the custard base twice through a fine-mesh sieve. Once after combining the warm cream with the egg yolks (catches the chalaza and any cooked bits), and once more before filling the ramekins. This is the difference between silky and chalky.
Sous vide at 176°F for 90 min for ramekins around 4 ounces. Bigger ramekins need 2 h. The custard should jiggle uniformly when nudged but not slosh. If it's still liquid in the center, give it another 15 min and re-test.
Use real vanilla beans, not extract. Split a bean lengthwise, scrape the seeds into the cream, and let it steep for 20 min off heat before mixing in the eggs. Extract works in a pinch but the flavor is paler and there are no visible flecks.
Sugar the top right before torching, not earlier. Sugar that sits on the cold custard for more than a few minutes starts to dissolve into the surface, which makes a thin, weak crust. Sprinkle, torch immediately, serve immediately. The contrast is everything.
Anti-tip: don't torch the rim of the ramekin. Heat the sugar surface evenly with the torch held a few inches away, moving constantly. Touching the rim will scorch the porcelain edge and leave bitter spots. Keep the flame in the center.
Silky tips
Skim any foam off the custard base before portioning to keep the surface smooth.
Use shallow dishes for faster setting and a higher caramel-to-custard ratio.
After chilling, leave uncovered in the fridge for 30 min to prevent condensation before torching.
Slightly Firm tips
Grease molds lightly and run a thin knife around the edge before unmolding.
Chill overnight for the cleanest slices; the custard firms as it rests.
If transporting, skip the sugar crust and top with brittle or toasted nuts instead.