Bring to a boil the whipping cream, remove from heat.
Add sugar and corn syrup in a saucepan. Cook until it gets amber brown, temperature should be 185°C (365°F).
Add butter cut in small cubes, reduce heat to medium.
Add hot whipping cream to the pan, little by little, while whisking.
If you want your caramel to be smooth and creamy, cook until it reaches 103-105°C (220°F).
If you want your caramel to be firmer, aim for 110°C (230°F).
Add salt if you want.
Put your caramel in a jar and let it cool down before putting in the fridge.
