Yellowfin Tuna Tostada Recipe

Make Candied Cashews

Line a small baking sheet with parchment. In a small nonstick skillet over medium heat, melt butter and add sugar. Stir until sugar dissolves and becomes syrupy (about 1–2 minutes). Add cashews and stir to coat completely. Continue cooking for 2–3 minutes, stirring constantly, until cashews are glossy and caramelized. Immediately transfer to the parchment, spreading in a single layer. Sprinkle fine sea salt over the warm nuts. Let cool completely, then roughly chop into bite-sized pieces.

Prepare Relish

Combine the diced mango, finely diced red chilli (remove seeds for less heat), minced shallot, chopped cilantro, lime juice, honey, and 1/4 tsp salt in a bowl. Taste and adjust seasoning — add a touch more lime or honey if needed. Refrigerate briefly while you prepare the tuna so flavors meld.

Season and Slice Tuna

Trim the tuna and pat dry. In a small bowl whisk together 2 tbs soy sauce, 1 tsp sesame oil, 1 tbs lime juice, 1/2 tsp kosher salt and 1/4 tsp black pepper. Place the tuna on a cutting board and brush or spoon half of the mixture over the fish, reserving the rest as a finishing drizzle. Using a very sharp knife, slice the tuna across the grain into 1/4-inch slices or into 1/2-inch dice depending on preference. If you prefer slightly marinated tuna, let sit 5 minutes; do not over-marinate to preserve texture.

Prepare Dressing and Finger Lime

Whisk together mayonnaise, Greek yogurt, rice vinegar, honey, and 1/8 tsp salt until smooth. If using finger limes, cut them in half lengthwise and gently press to release the pearl-like vesicles. If using a substituted small lime, reserve zest and segment thinly. Keep dressing chilled until assembly.

Assemble Tostadas

Lay out 6 tostada shells. Lightly brush each shell with a thin layer (about 1/2 tsp) of the creamy dressing to act as a base. Spoon 1–2 tablespoons of the mango-chilli relish onto each shell. Top with 2 oz (approximately 4 slices or a small handful of diced) seasoned yellowfin tuna per tostada. Scatter candied cashew pieces over the tuna (about 1 tablespoon per tostada). Spoon finger lime pearls over each (about 1/2 tsp per tostada) or sprinkle substitute lime zest/segments. Finish with a small handful of microgreens or a few cilantro leaves and a light drizzle of the reserved soy-lime mixture. Serve immediately with lime wedges on the side.