In a large mixing bowl, sift or whisk together the 2 cups all-purpose flour, 1 cup granulated sugar , 2 teaspoons baking powder, 1/2 teaspoon baking soda, 1/2 teaspoon ground cinnamon, 1/4 teaspoon ground nutmeg , 1/2 teaspoon salt.
In a medium sized mixing bowl or a large liquid measuring cup, whisk the 1/2 cup cooking oil, 2 large eggs, 1/2 cup sour cream or yogurt .
Make a well into the center of the dry ingredients and pour in the wet ingredients; stir until just combined. Fold in the 1 1/2 cups grated fresh pear and 1/4 cup nuts.
Pour batter into a well greased 9” x 5” loaf pan that has been lined with parchment paper.
In a small mixing bowl, combine the ingredients for the streusel topping: 1/3 cup all-purpose flour, 1/4 cup brown sugar, 1/4 teaspoon ground cinnamon . Cut in the cold 3 Tablespoons unsalted butter until crumbly. Sprinkle on top of batter.
Bake at 350℉ for 55-60 minutes, or until a toothpick inserted in the center of the loaf comes out clean. Allow to cool in pan 10-15 minutes, then run knife around the edges and turn loaf out onto a wire rack to cool completely.
Optional: once loaf is cool, in a small mixing bowl combine 1 cup powdered sugar and 2-3 teaspoons water; drizzle over loaf and allow to set before slicing.