Blackened Mahi Mahi

2 nice 6 to 8 ounce Mahi Mahi filets, I get mine from Trader Joes
1 cup beer
4 tablespoons butter divided
2 packages The SalsaKing Cajun Party Dip Mix
1/2 onion, finely diced
4 green onions, thinly sliced
1/4 cup The SalsaKing's Red Chile Merlot Mustard
3 tablespoons sour cream

Wash fish filets well and pat dry with paper towels. Open both packages of the dip mix and sprinkle over the fish filets. Melt the butter and lightly brush the filets with half. Place a large heavy skillet on stove and heat to medium heat. Allow to heat completely, 4 or 5 minutes. Place the filets in skillet and allow to cook without turning, 4 to 6 minutes, or until lots of smoke begins to come from filets. Turn and do the same for other side. Remove from skillet and place on serving platter. Add the remaining butter and sauté the onion. Add the beer and stir well, working up all the blackened bits from pan. Add the mustard and stir in well. Add the onions and sour cream, stirring in well. Pour over filets and serve.