Step 1

Add the everything except the oil to a small saucepan and place it over low heat. Stirring a bit, cook just to dissolve the sugar and warm the mixture, about 3 minutes.

Step 2

Remove the pan from the heat and use the back of a fork to macerate the blackberries. (I like keeping them partially intact.)

Step 3

Gradually whisk in the oil and blend until it's completely emulsified.