Melt 1/2 cup of unsalted butter in a medium saucepan over medium heat. Stir in 1 cup of dark brown sugar, simmer for 3-4 minutes until thickened. Add 1/4 cup of heavy cream, bring to a gentle boil, stirring constantly for another 3-4 minutes until smooth.

Remove from heat and stir in 1 cup of heavy cream and 1 cup of whole milk. If using bourbon, add it now. Gently heat until it reaches 165°F, ensuring everything is combined but not boiling.

In a large bowl, whisk together 5 egg yolks and 3/4 cup of granulated sugar until pale and thickened.

Slowly drizzle about 1 cup of the hot mixture into the egg yolk mixture while whisking continuously to temper the eggs. Once incorporated, pour it back into the saucepan, stirring until it reaches 165°F.

Stir in 2 teaspoons of vanilla extract and a pinch of kosher salt. Pour into a bowl, cover, and chill for at least 4 hours or overnight until completely cold.

Set up your ice cream maker and churn the mixture for about 25-30 minutes until thickened.

Transfer to a freezer-safe container, press down to remove air pockets, and freeze for at least 2 hours to firm up.

Let sit at room temperature for 5-10 minutes before serving for easier scooping. Enjoy!