The tuna slices need to marinate in the sauce for 30 minutes before serving.
Canned mango pulp in syrup, rather than fresh or frozen mango, is best for this recipe.
Deep brand is available online through Amazon.com and other food purveyors.
For the tuna
1½ pounds good-quality raw tuna (in one or two pieces)
¼ cup honey
2 teaspoons crushed red pepper flakes
1 teaspoon homemade or store-bought ginger-garlic paste (see NOTE)
2 tablespoons fresh lemon juice (from 1 lemon)
1 teaspoon kosher salt
¼ cup canola oil
Chopped cilantro, for garnish
For the salsa
¾ cup canned Alphonso mango pulp, such as Deep brand (see headnote)
¼ cup minced red onion
1 tablespoon minced red bell pepper (seeded)
1 tablespoon minced cilantro
½ teaspoon minced Thai green chile pepper (seeded)
2 teaspoons fresh lemon juice
½ teaspoon kosher salt
For the tuna: Cut the fillet(s) into 12 equal pieces that are about 1/2-inch thick (about 2 ounces each).
Whisk together the honey, crushed red pepper flakes, ginger-garlic paste, lemon juice and salt in a glass bowl, then add the tuna and toss to coat evenly.
Cover and refrigerate for 30 minutes.
Meanwhile, make the salsa: Stir together the mango pulp, red onion, bell pepper, cilantro, Thai chile pepper, lemon juice and salt in a medium bowl.
Cover and refrigerate.
When ready to assemble, heat the oil in a large skillet over medium-high heat.
Once the oil shimmers, lay the tuna slices in the pan, discarding their marinade.
Cook just long enough for a thin layer of the bottom sides of the tuna slices to turn white, then transfer to a platter.
To serve, stack 3 tuna slices on each plate so they alternate short and long.
Spoon about ¼ cup of the salsa over each portion, then top with the chopped cilantro.
Serve right away.
To make about 2 cups of ginger-garlic paste, combine ½ cup chopped (unpeeled) fresh ginger root, 1 ½ cups garlic cloves and ¾ cup water in a blender; puree on HIGH until smooth.
Transfer to an airtight container; seal and refrigerate for up to 1 week, or freeze for up to 3 months.
Adapted from "Rasika: Flavors of India," by Ashok Bajaj and Vikram Sunderam, with David Hagedorn.