Preparation

• Walnut Streusel: In bowl, stir together flour, sugar and salt. Using pastry blender or 2 knives, cut in butter until crumbly. Stir in walnuts. Set aside.
  
  In separate bowl, whisk together flour, baking powder, cardamom and salt.
  In large bowl, beat eggs with brown sugar until pale; beat in butter. Stir in flour mixture alternately with pear nectar, making 2 additions of flour mixture and 1 of pear nectar. Set aside.
  
  Pear Filling: Peel, halve and core pears; thinly slice crosswise. In bowl, toss together pears, sugar and flour. Set aside.
  
  Scrape half of the batter into parchment paper–lined 9-inch (2.5 L) square metal pan. Arrange pears over top. Dollop remaining batter over pears; spread evenly. Sprinkle with streusel.
  Bake in centre of 350°F (180°C) oven until golden and cake tester inserted in centre comes out clean, 1 hour. Let cool on rack.