Combine bread in a bowl with enough cold water to cover and stand until soft (2-3 minutes), then squeeze excess water from bread and transfer to a food processor.
Add the tarama paste, onion and lemon juice and process until smooth.
With the motor running, add olive oil in a thin steady stream and process until smooth and emulsified. Refrigerate until required.
Combine bread in a bowl with enough cold water to cover and stand until soft (2-3 minutes), then squeeze excess water from bread and transfer to a food processor.
Add the tarama paste, onion and lemon juice and process until smooth.
With the motor running, add olive oil in a thin steady stream and process until smooth and emulsified. Refrigerate until required.