⅓ cup (52 grams) plus 2 tablespoons (21 grams) fresh blueberries, divided
½ cup (84 grams) quartered fresh strawberries, divided
½ cup (90 grams) halved fresh blackberries, divided
Spiced Streusel (recipe follows)
Irish Cream Glaze (recipe follows)
Instructions
Preheat oven to 325°F (170°C). Spray a light-colored 9-inch springform pan with baking spray with flour; line bottom of pan with parchment paper.
In the bowl of a stand mixer fitted with the paddle attachment, beat butter and sugars at medium speed until fluffy, about 3 minutes, stopping to scrape sides of bowl. Add eggs and egg yolk, one at a time, beating well after each addition. Beat in vanilla bean paste.
In a medium bowl, whisk together 1⅔ cups (208 grams) flour, baking powder, and salt. In a small bowl, stir together sour cream and liqueur. With mixer on low speed, gradually add flour mixture to butter mixture alternately with sour cream mixture, beginning and ending with flour mixture, beating just until combined after each addition.
In another medium bowl, combine ⅓ cup (52 grams) blueberries, ¼ cup (42 grams) strawberries, and ¼ cup (45 grams) blackberries. Add remaining 1 teaspoon (3 grams) flour, tossing until well combined. Fold berry mixture into batter. Spoon batter into prepared pan, smoothing into an even layer with a small offset spatula. Sprinkle Spiced Streusel onto batter; top with remaining 2 tablespoons (20 grams) blueberries, remaining ¼ cup (42 grams) strawberries, and remaining ¼ cup (45 grams) blackberries.
Bake until a wooden pick inserted in center comes out clean, 1 hour to 1 hour and 5 minutes, rotating pan halfway through baking and loosely covering with foil to prevent excess browning, if necessary. Let cool in pan for 10 minutes. Remove sides of pan; let cool completely on base of pan on a wire rack. Drizzle with Irish Cream Glaze before serving.