Heat oven to 300℉/150℃.
In a large bowl, whisk together maple syrup, egg yolks, egg, maple sugar, and salt. Set aside.
In a medium saucepan, heat cream until it starts to bubble around the edges.
While whisking, slowly add a small amount of hot cream to egg mixture.
Continue whisking in small amounts of cream at a time, until fully incorporated.
Strain into a clean bowl.
Portion mixture into ramekins.
Place a clean dish towel in the bottom of a casserole.
Set filled ramekins on towel.
Pour boiling water in bottom of casserole, filling to half way up the ramekins.
Bake for 20-25 minutes until set.
Remove ramekins from water bath.
Refrigerate until ready to serve.
When ready to serve, sprinkle each custard with sugar.
Use a torch to brown sugar on top.