Preheat oven to 325 degrees. Spray a loaf pan with baking spray and line with a parchment paper, leaving about an inch or so over the sides of the pan to make for easy transfer. Set aside.
In a bowl combine the dry ingredients: flour, salt & baking soda. Give the mixture a quick whisk and set aside.
In a large bowl with an electric mixer (or use a stand mixer) beat the butter and sugar for 3 to 4 minutes, until pale and fluffy. Add the eggs one at a time and beat in well after each addition, scraping down the sides of the bowl, as necessary. Add in the mandarin zest, mandarin juice and vanilla and continue mixing, just until combined. Slowly add in the flour, about a ⅓ of the mixture and then add in half of the sour cream, continue mixing, and adding in the the flour and sour cream. Mix just until combined. Do not over mix the batter.
Scrape batter into the loaf pan and level the batter. Bake in the oven for 55-60 minutes, loaf is done when a toothpick inserted in the center comes out clean.
Allow the loaf to cool in the pan for about 20 minutes before transferring to a cooling rack.
Making the glaze: add the powdered sugar and juice to a small bowl and whisk together until combined and smooth. Pour over the loaf before cutting it into slices. Sprinkles extra mandarin zest over the glaze if desired.