Melt the butter in a pan.
Add the pecans, toss to coat, sprinkle on the sugar and heat until the pecans are nice and toasted, about 3-4 minutes.
Remove the pecans from the heat and let cool completely.
Heat the maple syrup, cream and milk in a sauce pan until it almost boils, about 5 minutes.
Reduce the heat to low.
Temper the eggs and stir them into the cream.
Cook at low heat until it thickens and can coat the back of a spoon.
Remove from heat and stir in the bourbon.
You may want to strain the mixture at this point to remove any bits that may have formed while warming.
Chill the mixture in the fridge.
Freeze the maple custard and toasted pecans according to the instructions for your ice cream machine.