Prepare the Bread (if using bread): Soak the stale bread in water or milk until softened. Squeeze out excess liquid and crumble the bread into small pieces. If using potatoes, ensure they are boiled, peeled, and mashed smoothly.

Blend the Base: In a food processor, combine the soaked and crumbled bread (or mashed potato), grated onion, and minced garlic (if using). Blend until smooth.

Add the Fish Roe: Add the tarama (fish roe) to the food processor and blend until well combined with the bread or potato mixture.

Emulsify the Mixture: With the food processor running, slowly drizzle in the olive oil in a steady stream. This process is similar to making mayonnaise and helps to emulsify the mixture, creating a smooth and creamy texture. Gradually add the lemon juice while continuing to blend. Adjust the amount of lemon juice based on your taste preference.

Season and Adjust: Taste the taramosalata and season with salt and pepper as needed. If the mixture is too thick, you can add a little water or milk to achieve the desired consistency.

Chill and Serve: Transfer the taramosalata to a serving bowl and refrigerate for at least 1 hour to allow the flavors to meld. Before serving, garnish with olives and fresh herbs if desired. Serve with pita bread, crackers, or vegetable sticks for dipping.