Heat the sugar in a medium saucepan over medium heat, stirring constantly with a spatula or wooden spoon.
Sugar will form clumps and eventually melt into a thick, golden liquid as you continue to stir. Do not burn. As soon as all the sugar has melted into a golden/amber liquid, immediately add the butter. Be careful as the caramel will bubble rapidly.
Stir the butter into the caramel until it is completely melted (around 2 - 3 minutes)
Very slowly, drizzle the cream into the mixture, stirring constantly. Be careful as the mixture will bubble and splatter. Allow the mixture to boil for 1 minute. It will rise in the pan as it boils.
Remove from heat and stir in salt. Allow to cool down before using. Store caramel in an airtight container and refrigerate for up to 2 weeks.