1. Preheat oven to 180°C and marinate pork tenderloin with mustard, salt and Sichuan pepper all round.
2. Heat up pan to high heat, add olive oil, and sear marinated pork tenderloin until browned on all sides.
3. Transfer pork tenderloin into preheated oven and roast for 20 to 30 minutes. Set aside to rest.
4. Meanwhile, blend eggs, capers, tuna and anchovy fillet in a food blender and blend till smooth paste.
5. Lastly, blend in olive oil and lemon juice, season to taste.
6. Slice pork tenderloin thinly, arrange on a plate, and spoon over tuna sauce. Garnish with sliced lemon and chopped parsley.
7. Taste for seasoning and serve.