Step 1

Melt the butter in a heavy saucepan over medium-low heat.

Step 2

Add the remaining ingredients, raise heat to medium-high and bring to a boil, stirring constantly (will take 5-10 minutes, depending on your stove).

Step 3

Lower heat to medium or medium-low (or what you need to keep a very low boil) and cook for 3 minutes, stirring constantly (really- this is not the thing to walk away from! It will burn...I know from experience!).* Remove from heat and stir in vanilla, if using.

Step 4

Melt the butter in a large microwave safe bowl (I use an 8-cup glass measuring cup with handle) - about 30 seconds.

Step 5

Add the brown sugar, honey, and condensed milk to the bowl and whisk until all is incorporated fully.

Step 6

Microwave on high power for 4 minutes. It will look lumpy and ruined - it's NOT. Whisk it hard until it smooths out, about 30 seconds. Test the temperature with an instant read thermometer - it should be at 220-225 degrees Fahrenheit. Microwave again for another 30 seconds if it's not (mine is usually 221-222 at 4 minutes).

Step 7

Stir in the vanilla, if you're using.

Step 8

For both methods, let cool a bit and then pour into a glass serving bowl and serve warm.

Step 9

Refrigerate any leftovers. Microwave a few seconds to soften before using again.