This reminds me of the hot fudge sauce from Dairy Queen that we used to love as kids. I was the one who always ordered extra sauce. Since this version of a DQ-style sauce is dairy-free, I prefer to think that the D in DQ stands for “Dreena”!
Combine all the ingredients in a blender (preferably high-speed; see note). Blend on the soup function to puree and then warm and thicken the sauce. You may need to puree a little more depending on your blender. The sauce should be quite warm when finished. Transfer to a container to cool slightly, or allow to cool in the blender jar. The sauce will thicken more as it cools. Serve warm, or allow to cool completely.
Notes
Milk Note: This sauce thickens after pureeing. With 1/2 cup of milk, the sauce will be pourable, with just a slightly thick consistency. If you want a very thick sauce, use less milk, about 1/3 cup. Keep in mind that it thickens as it cools as well. You can also thin the sauce after it cools, stirring in a touch more milk. Almost any type of nondairy milk will work here, but with oat milk, the mixture can become too sticky and thick.Blender Note: A high-speed blender works best, and especially using the Blendtec twister or wildside jar. If you’re using a standard blender, puree as long as needed to get a smooth texture. Once smooth, transfer to a small saucepan to warm and thicken over medium-low heat, whisking occasionally, until a slow bubble develops. Then, remove from the heat and serve hot or warm, or let cool and store in a covered jar in the fridge for up to 5–6 days.