Melt <quantity>200<unit>g</unit></quantity> of butter in a saucepan over medium heat

Cook the butter until very light brown, stirring continuously. Remove from the heat

Add <quantity>1<unit>tbsp</unit></quantity> of fish sauce and <quantity>1<unit>tbsp</unit></quantity> of miso. Whisk until combined. The miso glaze is ready

Prepare the grill with charcoal and light it

Pat dry <quantity>1<unit>fillet</unit></quantity> of cod with a paper towel

Run the knife between the flesh and the skin from tail to head, while pulling the skin in the opposite direction. Flip and trim any remaining skin

Cut the cod into <quantity>1.5<unit>in</unit></quantity> pieces

Turn the cod pieces on their sides and insert <quantity>2</quantity> metal skewers in each piece

Transfer the cod to a tray, and generously brush the miso glaze on all sides

Grill the cod pieces on both sides until lightly charred and slightly firm to the touch. The grilled cod with miso glaze is ready

Enjoy! Serve this at a barbecue to impress your friends!