01 -
Drain blueberries using a fine mesh strainer into a large liquid measuring cup. Add enough water to the collected syrup to total 4 cups of liquid.
02 -
Pour the liquid into a medium saucepan and bring just to a simmer over medium heat. Remove from heat and whisk in strawberry gelatin powder until fully dissolved and smooth, about 1 to 2 minutes.
03 -
Place a few cups of ice cubes and water in a large bowl to create an ice bath. Lower the bowl containing the gelatin mixture into the ice bath. Stir intermittently until the gelatin thickens to a lightly gelled, wobbly state at 45 to 55 degrees Fahrenheit, approximately 30 minutes.
04 -
Remove the gelatin bowl from the ice bath. Stir in the sour cream until mostly incorporated with some white streaks remaining. Gently fold in the blueberries.
05 -
Pour the mixture into a 10½-cup Jell-O mold or bundt pan. Tap gently to remove air bubbles. Cover with plastic wrap and refrigerate until fully set, at least 8 hours or overnight.
06 -
Dip the mold briefly into warm water (approx 10 seconds), then invert onto a serving plate. Repeat dipping and inverting as needed until mold releases smoothly.
07 -
Slice the molded gelatin with a cake server and serve immediately. Refrigerate leftovers tightly covered for up to 3 days.