Step 1

Preheat the oven to 350°F. Spray a 9x5x3-inch loaf pan with nonstick spray.

Step 2

In a large bowl, use an electric mixer to combine the sugar and butter. Beat in the eggs and vanilla.

Step 3

In a separate bowl, whisk together the flour, baking soda and salt. Add the dry ingredients to the wet ingredients a little at a time, alternating with the buttermilk. Stir in the apples and nuts (if using). Spread the batter evenly in the prepared pan.

Step 4

In a medium bowl, stir together the flour, sugars and cinnamon. Then use a pastry cutter to cut in the butter until the mixture resembles crumbs. Sprinkle the streusel on top of the batter in the pan.

Step 5

Bake for 50 to 55 minutes, or until a toothpick inserted into the center comes out clean.