Preheat oven to 350 degrees Fahrenheit. Grease and flour a loaf pan and set aside.
In a large bowl, combine flour, baking soda, cinnamon, and salt. Whisk in butter, eggs, vanilla extract, and apple cider. Fold in grated apples. Set aside.
In a small bowl, mix together sugar, cinnamon, and flour to create the streusel. Cut in the butter until pea-sized balls form. Spread half of the streusel in the bottom of the pan. Pour the batter in the pan. Top the batter with the remaining half of the streusel.
Bake for 60-75 minutes or until a toothpick is inserted in the center and comes out clean. Cool on a wire rack before removing from the pan.