Step 1

Add frozen raspberries to a medium saucepan and heat over medium-high until berries break down, about 10 minutes.

Step 2

Bring raspberries to a light boil, stir in sugar, and return to a boil.

Step 3

In a separate small bowl, whisk together corn starch and water and pour into the raspberries.

Step 4

Stir the mixture vigorously for 1 minute and then remove from heat and let cool and thicken, stirring occasionally.

Step 5

Bottle up and store in the fridge or freezer, or use right away.