I finally found it!
Bratten’s Halibut au Gratin
Halibut – 6 oz. Per person
Poach fish until done- about 10-15 minutes
Melt and simmer:
3Tbs. Butter
1 Tbs. Flour xxx : GF use cornstarch
2 cups half & half
1/8 tsp garlic powder (I use one clove fresh garlic – minced)
1/4 tsp. Dry mustard (Important)
Salt and Pepper
Simmer the above until thick.
Add: 1/2-cup mild cheddar cheese, grated (I use sharp)
Simmer until melted and thick, but not too thick. Add milk to th.in if necessary.
Drain poached fish. Pour sauce over top. Add more grated cheese. Bake in a 350-degree oven for 10 minutes.
Bratten's Seafood Grotto was a wonderful restaurant on 4th South in Salt Lake City up until the mid-late 1980's I loved it! Carla and Gaylen introduced me to it the summer I lived with them when I was 17.
When I went thru the Salt Lake Temple for my endowments we went there for dinner after the session and it was so good and such a celebration. All my Aunts and Uncles were there and so were Mom and Daddy and Granny B and of course Stephen and his parents.