Brown butter gives this ice cream a rich, nutty flavor and caramel-like complexity. I went all out and used 1 cup of butter to get plenty of those delicious browned bits—because more is always better, right? Just toss those magical brown butter solids into the ice cream and save the clarified butter for some other use like drizzling over popcorn. Trust me, nothing’s going to waste here!
Add the butter to a large skillet or saucepan (a light colored pan works best so you can watch the butter solids brown). Cook over medium heat stirring frequently until it turns golden brown. It will take about 8 minutes and it will foam and sizzle. Push the foam aside occasionally to check the color.
Carefully pour the clear liquid (clarified butter) into a bowl and save for another use.
Transfer the browned bits to a saucepan. It is ok if a few tablespoons of the clarified butter gets mixed in but too much will make the ice cream have a greasy feel in your mouth. The extra flavor comes from the browned bits of milk solids and you will use these in the ice cream.
Pour the milk, brown sugar, salt, and corn syrup (if using) into the pan with the browned butter bits. Heat over medium heat until the mixture is hot and comes to a gentle simmer.
In a medium bowl, whisk the egg yolks well. Then, while constantly whisking, slowly pour about ½ cup of the hot milk mixture into the yolks to temper them.
Now, slowly pour the tempered egg mixture back into the pot with the hot milk, whisking constantly. Cook over medium-low heat, stirring continuously, for 5 to 8 minutes until the mixture thickens slightly. The mixture should reach 180°F on an instant-read thermometer. If you don't have a thermometer, the mixture should be steamy hot (but not boiling) and thick enough to leave a trail when you run your finger across the back of a spatula.
Pour the mixture through a strainer into a bowl. Stir in the cream and vanilla extract then cover and refrigerate for 4 hours or until chilled.
Pour the mixture into an ice cream maker and follow the manufacturers directions for churning ice cream.
Once the ice cream has the consistency of soft serve, add the toffee bits.
Transfer the ice cream to a freezer-safe container. I prefer using a bread pan because its rectangular shape makes scooping easy.
Freeze for at least 4 hours.
Notes
Cut the butter into small cubes to ensure even melting.
Use a light-colored skillet so you can easily see when the butter solids begin to turn brown.
You can use the reserved clarified butter as you would regular butter, except it is better. It has a nuttier flavor and higher smoke point so it doesn’t burn as easily.
The corn syrup is optional but I like to add it because it helps prevent ice crystals from forming in the ice cream and gives it a smoother, creamier texture.