Begin by placing your KitchenAid mixing bowl in the freezer for at least 15 hours.

In a medium mixing bowl, vigorously whisk together the egg yolks and 1/4 cup of granulated sugar until pale and thickened.

In a saucepan over medium heat, warm the whole milk until it reaches 165°F, stirring frequently.

Carefully drizzle the warm milk into the egg mixture, whisking continuously to prevent curdling.

Return the mixture to the saucepan, add the remaining sugar, and cook on low heat until thickened, about 5-7 minutes.

While the custard cools, brew a strong cup of coffee and let it cool slightly to room temperature.

In a large bowl, combine the tempered egg mixture, cooled coffee, heavy cream, vanilla extract, and a pinch of salt.

Cover the bowl and refrigerate for at least 4 hours.

Once chilled, pour the mixture into the chilled KitchenAid bowl and churn on medium speed for 25-30 minutes.

Gently fold in the chopped toffee bars into the churned ice cream.

Transfer your ice cream to a freezer-safe container, smoothing the top with a spatula, and let it firm up in the freezer for a couple of hours.