For 5 servings

• Small amount of vegetable shortening and flour for preparing pan
• 1 cup toasted walnuts or pecans, coarsely chopped🛒
• 1/3 cup firmly packed light brown sugar
• 1 teaspoon ground cinnamon🛒
• 1/3 cup all-purpose flour
• ¼ cup unsalted butter, chilled
• 2 Bosc or Bartlett pears (about 2 cups), peeled, cored, and coarsely chopped
• 2 teaspoons freshly squeezed lemon juice
• 1¾ cups all-purpose flour
• ¾ teaspoon baking powder
• ½ teaspoon baking soda
• ¼ teaspoon salt
• ½ cup unsalted butter, room temperature
• 1 cup granulated sugar
• 2 large eggs
• 1 teaspoon pure vanilla extract🛒
• 1 cup sour cream