Cream:

 Combine raisins and garlic in small saucepot. Cover with water. Bring to a boil and simmer until raisins are plump and garlic cloves are very tender. Drain and set aside.

 Char, peel and seed jalapeños. 

In food processor, combine raisins and garlic with jalapeños, mayonnaise, buttermilk, ginger, lime juice, salt and oil.  Process until very smooth. Chill.

Tuna Steaks:

 Lightly season tuna steaks with sea salt. Sear to rare (145°F) in very hot skillet. 

Cool to room temperature. Slice thin. Set aside.

To serve: Slice mushrooms, lenthwise, 1/4-inch thick. Arrange slices of mushrooms in single layer on serving tray and arrange a slice of tuna on each. Top with a dollop of Golden Raisin-Ginger Cream and sprinkle with sea salt and cilantro leaves.

Source: Chef Robert Del Grande and California Raisin Marketing Board