• Add the egg yolks and brown sugar to a large bowl. Whisk vigorously or mix with an electric mixer until light and fluffy.
• In a medium saucepan, add the whole milk and salt. Heat to a gentle simmer, but do not boil.
• Slowly pour the warm milk into the egg yolk mixture while whisking or mixing with an electric mixer so the yolks don't curdle.
• Add everything back in the saucepan and place over medium-low heat. Cook, stirring constantly, until the temperature reaches 170°F on a digital instant thermometer*. Make sure you are stirring the entire time or it may curdle.
• Turn the heat to low and stir in the butter until melted.
• Strain the custard through a sieve and into a bowl. Cover the surface with plastic wrap and allow to cool completely in the fridge for at least 1 hour or overnight*. To speed up cooling time, vigorously whisk the custard or beat with an electric mixer to get rid of the heat, and place the bowl over an ice bath.
• Add the cold heavy whipping cream to a large bowl and use an electric mixer to beat until thick and fluffy. Fold the whipped cream into the cooled custard.
• If making with an ice cream maker: Churn the ice cream as instructed by your ice cream maker until thick with a consistency of soft serve. Transfer the ice cream to a bowl or a 9 x 5" loaf pan and cover the top with plastic wrap. Freeze for 1-3 hours or until frozen to your desired consistency.
• If making without an ice cream maker: Transfer the ice cream to a bowl or a 9 x5" loaf pan. Cover with plastic wrap and press the plastic wrap to the surface of the ice cream to prevent ice crystals from forming. Freeze for 6 hours or overnight.

Homemade Butterscotch Sauce:

• Add the butter, brown sugar, corn syrup, and salt to a medium saucepan. Place the pan over low heat and cook, stirring occasionally, until the butter and sugar are melted and the sugar isn't grainy.
• Stir in the heavy cream over low heat until the sauce is smooth. Remove from heat and transfer to a glass container to cool.