Tartare sauce

Name: Tartare sauce
Prep time: 10 min
Cook time: 10 min
Total time: 20 min
Cuisine: European, Mediterranean, French
Ingredients: 1 pickled gherkins (approx. 20 g); 1 sprig fresh flat-leaf parsley, leaves only; 3 - 4 fresh chives or 1 tsp dried chives; 1 egg; ½ tsp mustard powder; 1 tsp lemon juice; ½ tsp fresh tarragon, leaves only or 1/4 tsp dried tarragon; ½ tsp sea salt; 1 tsp ground black pepper; 2 tsp white wine vinegar; 200 g grapeseed oil; 2 tsp pickled capers, drained