Mix together the sugar, yogurt, jam, salt, eggs, and oil.
In a separate bowl, mix together the flour, baking powder, and baking soda.
Add the dry mixture to the wet mixture and mix until just combined.
Grease a loaf pan and pour in half the mixture.
Optional: Add a few tablespoons of jam and swirl into the mix. Sprinkle in half of the blueberries.
Pour the remaining half of cake mixture.
Optional: Swirl some additional jam.
Sprinkle in the remainder of the blueberries.
Bake at 350F for approximately 1 hour until a toothpick comes out clean. If the top of the loaf is getting too brown, cover with foil.
