1. Preheat oven to 325 F. Line loaf pan with parchment paper.
2. Combine eggs and sugar. Whip on high for 2-3 minutes. Gently incorporate sour cream into egg mixture.
3. In a medium bowl, combine flour, baking powder and salt. Whisk together dry ingredients.
4. Fold dry ingredients into the egg mixture in thirds.
5. Slowly whisk in melted butter. Once mixed, divide one third of the batter into separate bowl.
6. Mix in black sesame paste into the third of the batter until just combined.
7. Pour plain batter into prepared loaf pan. Spoon in dollops of black sesame batter throughout loaf pan. Using a knife, make swirl pattern through sesame batter.
8. Bake for 55 minutes to 1 hour.