Step 1

Stir the sugar, corn syrup and water together in a 3-4 cup microwave-safe measuring cup or glass bowl.

Step 2

Microwave on high (full) power until the mixture is just beginning to brown, 4 to 8 minutes (depending on the strength of your microwave. Check at 4 minutes and every 15-30 seconds after.).

Step 3

Remove the caramel from the microwave and set aside for 5 minutes or until it darkens to a rich honey brown.

Step 4

Carefully, add heavy cream (the mixture will be hot). If you end up with any lumps of caramel, just return the sauce to the microwave for 30 seconds and stir well again. Repeat as needed.

Step 5

Add butter and vanilla. Whisk ingredients together till smooth. The mixture will thicken a bit as it cools.

Step 6

If not using right away, transfer to a jar with a tight-fitting lid and store in the refrigerator. Warm slightly in the microwave before serving.