Boil maple syrup in a small saucepan for about 5 minutes over medium-high heat, stirring constantly. When syrup is amber color and has reduced, remove from heat and add half-and-half and salt to the pan. Stir to combine and bring it to a boil over medium-high heat. Once you see the first bubbles surfacing, remove from heat and set aside.
Whisk egg yolks and sugar in a medium bowl until light in color. Temper the eggs with the maple-cream mixture. To do that, start by adding about 1/3 cup of the mixture to the yolks, while whisking. Once that’s incorporated, add maple-cream mixture to yolks slowly in a stream, always whisking.
Pour mixture back in saucepan through a sieve to catch any egg bits that might have curdled.
Re-heat mixture over medium heat, always stirring, for about 1-2 minutes. Don’t let mixture come to a boil. If you use a thermometer, the temperature should read somewhere between 145F and 160F. Don’t let it pass this temperature. That’s the range of temperature in which eggs cook.
Transfer mixture to a bowl, through a sieve, again to catch any bits of eggs that might have curdled. Add vanilla and stir. Cover and store in refrigerator for a few hours to overnight.
On the next day, remove mixture from the fridge and churn in your ice cream maker according to manufacturer’s directions.
Store ice cream in the freezer for a few hours before serving.
To serve, either spoon ice cream over cold pie or heat the pie for a few seconds in the microwave.