Step 1

Heat the canola oil in a large, deep skillet. Add the ginger, lemongrass and jalapeño and cook over high heat until fragrant, about 1 minute. Add the mussels and water and toss to coat. Cover and cook, stirring occasionally, until the mussels open, about 5 minutes. Using a slotted spoon, transfer the mussels to a large, deep bowl; discard any mussels that do not open.

Step 2

Carefully pour any accumulated mussel liquid back into the skillet. Stir in the brown sugar, Asian fish sauce, unsalted butter and minced cilantro. Pour the pan sauce over the mussels and serve immediately.