01 - Preheat oven to 350°F. Grease and line a 9x5-inch loaf pan with parchment paper for easy removal.
02 - In a large mixing bowl, whisk flour, granulated sugar, ground cinnamon, baking powder, baking soda, and salt until evenly blended.
03 - In a separate bowl, beat eggs thoroughly. Add vegetable oil, buttermilk, and vanilla extract, whisking until well combined.
04 - Pour wet mixture over dry ingredients. Stir gently with a spatula until just combined, taking care not to overmix to achieve a tender crumb.
05 - Fold cranberries and nuts (if using) carefully into the batter, ensuring even distribution.
06 - Spread batter into prepared loaf pan and level surface. Evenly sprinkle coarse sugar over the top if desired.
07 - Bake in preheated oven for 50 to 60 minutes, or until a toothpick inserted into the center emerges clean.
08 - Allow loaf to cool in pan for 10 minutes before transferring to a wire rack. Cool fully prior to slicing to maintain texture.