Blueberry-Poppy Seed Squares (Borůvkový Koláč)

Blueberry-Poppy Seed Squares (Borůvkový Koláč)
Blueberry-Poppy Seed Squares (Borůvkový Koláč)
The floral character of poppy seeds shines when paired with blueberries in this rich dessert.

The floral character of poppy seeds shines when paired with blueberries in this rich dessert. Store any unused seeds in the refrigerator or freezer.

Blueberry-Poppy Seed Squares (Borůvkový Koláč)
The floral character of poppy seeds shines when paired with blueberries in this rich dessert.
Yield: serves 12

Ingredients

  • 20 tbsp. unsalted butter, softened, plus more for pan
  • 3 cups flour, plus more for pan
  • 1 12 cups sugar
  • 34 tsp. kosher salt
  • 14 tsp. vanilla
  • 4 cups blueberries
  • 2 tbsp. fresh lemon juice
  • 12 tsp. ground cinnamon
  • 1 12 cups ground poppy seeds (available at Kalustyan's)
  • 12 cup heavy cream

Instructions

  1. Heat oven to 350°. Butter and flour a 9" x 13" metal baking pan; set aside. Beat 16 tbsp. butter and 12 cup sugar on medium-high speed of a mixer until pale and fluffy, about 2 minutes. Add 2 12 cups flour and 12 tsp. salt; beat until just combined. Press dough into bottom and halfway up sides of prepared pan; chill for 20 minutes. Bake crust until lightly browned, about 12 minutes; let cool. Meanwhile, stir remaining butter, flour, and salt, 14 cup sugar, and vanilla in a bowl until coarse crumbles form; set streusel aside.
  2. Heat remaining sugar, 3 cups blueberries, lemon juice, and cinnamon in a 2-qt. saucepan over medium-high heat; cook until berries burst, about 20 minutes. Remove from heat and stir in remaining berries; let cool. Stir together poppy seeds and cream in a bowl; spread evenly over cooled crust. Pour blueberry mixture over poppy seeds; sprinkle with streusel mixture. Bake until filling is bubbly and streusel is lightly browned, about 40 minutes. Let cool, cut into squares, and serve.