1. Coat an 8" square baking dish with cooking spray and set aside.

2. Puree berries, accumulated juices, and water in a blender until smooth, about 15 seconds. Transfer puree to a large saucepan.

3. Whisk in sugar and lemon juice and bring to a boil over medium-high heat, whisking frequently to dissolve sugar. Continue to cook, stirring constantly and scraping down sides and bottom of pan as needed, until mixture reaches 230°F, about 15 minutes.

4. Stir in pectin, return to a boil, and cook 1 minute. Transfer to prepared pan and quickly spread into an even layer. Let sit at room temperature until firm and fully set, 3 to 4 hours.

5. When mixture is set, sprinkle a thin layer of sugar on a cutting board, then add more sugar to a shallow bowl. Run a knife around edges of pan and turn over onto the prepared cutting board.

6. Slice candies into 3/4" squares. Working with a few pieces at a time, toss in sugar to coat all sides evenly. Serve immediately or refrigerate in an airtight container for up to 5 days.