Whisk together the milk, cream, sugar, cornstarch, corn syrup, and salt.
1 ¾ cup whole milk, 1 cup heavy cream, ½ cup granulated sugar, 1 ½ tbsp cornstarch, 2 tbsp light corn syrup, ½ tsp kosher salt
Place over medium-high heat, stirring occasionally until the mixture starts to steam. Continue to whisk and bring the mixture to a boil. When boiling throughout, remove from heat.
Whisk in vanilla extract and lemon curd. Pass through a strainer if needed.
½ tsp vanilla extract, 1 cup lemon curd
Cool off slightly, 5-8 minutes.
Pour into an airtight container and chill 8-10 hours.
To freeze, remove from refrigerator and pour into ice cream freezer. Follow the directions with your freezer; each one can vary. My KitchenAid stand mixer (affiliate link) with ice cream maker attachment(affiliate link) takes about 20-25 minutes to freeze fully. While freezing, make Swiss meringue.
For the Swiss meringue
In the bowl of an electric mixer, combine the egg whites and sugar. Set over a kettle of barely simmering water and add salt.
2 egg whites, ½ cup granulated sugar, ½ tsp kosher salt
Whisk constantly until sugar is dissolved and the temperature reaches 160°F.
Remove from heat and place bowl on the mixer fitted with the whisk beater and add vanilla extract.
1 tsp vanilla extract
Beat until the mixture becomes white, voluminous and reaches room temperature, 8-10 minutes.
Fold meringue into frozen ice cream and place in the freezer for 4-6 hours.