In a medium saucepan, whisk together sugar, cornstarch, and salt. Stir in ⅓ cup (80 grams) water until well combined; stir in ⅔ cup (100 grams) strawberries and ⅓ cup (65 grams) raspberries. Bring to a boil over medium heat, stirring frequently; cook until thickened, some berries have broken down, and an instant-read thermometer registers 200°F (93°C), about 4 minutes. Stir in blueberries, liqueur, remaining ⅔ cup (100 grams) strawberries, and remaining ⅓ cup (65 grams) raspberries. Remove from heat; transfer to a medium bowl, and let cool completely.
Recipe by Bake from Scratch at https://staging.bakefromscratch.com/berry-shortcake-bundt/