Shrimp Creole Au Gratin

Or something lol This is something I learned from my friend Gelena, and it is delicious. Anyone I have made it for instantly drools over it. It sounds a little weird, and it isn't exactly good for you lol but sonofabitch is it ever tasty!! Some measurements are approximate, because I don't have an actual recipe for it, just learned it by watching her make it! If you are the kind of cook that needs an exact recipe to follow to cook, this might not be the recipe for you lol! But if you're cool with winging it and throwing shit together, then gets to cookin'!!

2 box Zatarain's dirty rice (there is a low sodium variety available)
3 stalks celery, diced
about half a medium onion, diced
butter (you'll need a good 4 tbsp or so)
about 1 and 1/2 lbs ground beef ( i get the biggest package over 1 lb I can find but you don't quite need 2 lbs)
2 lbs shrimp (i get 2 bags frozen shrimp, 1 lb each), thawed, peeled
2 egg yolks
flour (you'll use the same amount of flour as butter, to make a roux, so about 4 tbsp)
milk (this one is a tricky measurement...you probably need at least a cup, maybe up to 2 cups. You have to add it in a little at a time til the sauce is a saucy consistency lol)
Tony Chachere's creole seasoning
salt and pepper to taste
1-2 bags sharp cheddar (enough to cover top of 13x9 casserole)

Cook rice per package directions, with ground beef. In skillet, saute celery and onion in 2 tbsp butter til tender, push to side. Add 2-3 more tbsp butter, melt, then equal amount of flour to make roux (remember you already added 2 tbsp of butter to cook the onion and celery in, so add those 2 tbsp of flour too. So if you add 2 more tbsp of butter after cooking the onion and celery, you'll need a total of 4 tbsp flour. Got it? Hope so!). Cook til golden and bubbly, using a whisk to stir often. Whisk in milk- start slowly, about 1/2 cup at a time. Keep that whisk moving to get the milk into your roux. You want the sauce to be thick, but creamy, so add small amounts of milk, stirring between each addition, to get the right consistency. Add the 2 egg yolks, stir well. Bring to boil. Stir in a handful or 2 of shredded sharp cheddar, allow to melt. Now for the seasonings- I'd say start with a teaspoon of creole seasoning, stir well. Give it a taste. If you don't taste the spice, which you probably won't at that point (I probably add about a tbsp or more of seasoning), add another teaspoon. Again, stir and taste. If you want more flavor, then keep adding little bits of seasoning at a time. The salt and pepper are optional, it may be salty and peppery enough for your tastes with just the creole seasoning. Once you get the consistency and flavor right, add shrimp and stir. Pour sauce mix into a 13x9 casserole dish, top with cheese to cover (we like lots of cheese). Bake at 350 for about 30 minutes, or til cheese is melty and casserole is bubbly. Serve over the prepared dirty rice.
This makes a lot, you could halve the recipe easily. When I make it just for us at home, I only make half.