Seared Tuna with Pistachio Crust and Papaya Salsa

I don't know how I forgot to post this recipe (although I vaguely recall making this the night before I left town for a week), but I apologize for holding out on you. The papaya salsa on this is great on its own, but of course perfectly cooked tuna is a beautiful thing and with a pistachio crust, it only gets better.

One year ago: Fresh Fig and Raspberry Tart with Honey
Three years ago: Mole Risotto with Avocado Puree

Seared Tune with Pistachio Crust and Papaya Salsa (from Ottolenghi)
Ingredients
150g shelled pistachio nuts
grated zest of 1 lemon
1 kg tuna loin
2 tbsp olive oil
5 tbsp Dijon mustard
coarse sea salt and black pepper
Papaya salsa
1 mini cucumber, peeled, seeded, and cut into 1cm cubes
1 large papaya, peeled, seeded, and cut into 1cm cubes
1 large mango, peeled, stoned, and cut into 1cm cubes
2 red chilies, finely choppedool completl
10g fresh ginger, grated
1 small red onion, finely chopped
grated zest and juice of 2 limes
2 tbsp lemon juice
2 tbsp fish sauce
4 tbsp olive oil
2 tbsp sugar

1. Place salsa ingredients in bowl, stir together, and season with salt and pepper. Chill and let rest for at least 1 hour.
2. Preheat oven to 500F.
3. Chop pistachios in food processor to fine crumbs. Scatter on baking tray with lemon zest.
4. Cut tuna loin into 2 or 3 cylindrical pieces. Brush with olive oil and season with salt and pepper.
5. Place a cast iron pan on high heat and heat up. Sear tuna pieces for 3 - 4 minutes total. Remove from pan and set aside.
6. Brush tuna with mustard and roll in pistachios.
7. Place tuna in baking tray, transfer to oven, and roast 5 - 6 minutes or until done. Remove and allow to cool completely.
8. Cut tuna into 2cm thick slices. Serve with salsa on the top or to the side.