- 1 egg yolk, at room temperature
- 3 1/2 tablespoons sunflower oil, or as needed, divided
- 1 tablespoon Dijon mustard
- salt and ground black pepper to taste
- 2 ripe avocados, sliced
- 12 ounces precooked prawns, peeled and deveined
- Combine egg yolk, 1 teaspoon sunflower oil, and Dijon mustard in a bowl; whisk until smooth. Pour in remaining oil gradually, continuing to whisk, until sauce is smooth. Season with salt and pepper.
- Arrange avocado slices in the center of a serving platter. Scatter prawns around the avocados. Pour sauce over avocado.