Thaw frozen raspberries until soft and easy to handle. Dump about 2 cups of the raspberries into a fine mesh strainer and press the mixture until the liquid has come out and seeds are left in the strainer. It should look like a seedless raspberry sauce right now.

In a small pot, whisk together all the ingredients and place over medium heat.

Whisk occasionally, and when mixture starts to bubble/thicken, whisk constantly for about 5 minutes. When mixture is thick/goopy, remove from heat and let cool on the counter.

Whisk every 5-10 minutes or so as it cools, and when it is cool enough to handle, scoop into a jar and refrigerate to store.