Start by tearing the stale bread into small pieces and placing them in a bowl. If the bread is too fresh, you can leave it out to dry for a few hours or toast it lightly.
In your blender or food processor, combine the fish roe, chopped onion, and lemon juice. Blend until smooth.
Next, add the pieces of stale bread to the mixture. Blend again until the bread is fully incorporated, creating a smooth paste.
With the blender running, slowly drizzle in the sunflower oil. If the mixture is too thick, you can add a little water to achieve your desired texture.
Once blended, taste your Taramosalata and adjust the seasoning as needed. You can add more lemon juice for acidity or more fish roe for a stronger flavor.
Transfer the dip to a serving bowl and refrigerate for at least an hour before serving.