THIS IS A DOUBLE DECOCTION MASH RECIPE!
To do a decoction mash properly you will want to remove 1 quart of thick mash per pound of grain (in this case 10 quarts). The decoctions are timed for after the dough-in and after the Beta Amylase Rest. Then you increase the heat to mash out and transfer to the boil kettle to add the hops.
You can use any hops you have lying around because they won't impart much aroma, if any, but aim for 20 IBU. If you want to be authentic about it use a German hops varietal like Spalt.
The yeast you use can vary, but try to use a German lager yeast, and none of that hefeweizen phenol crap, this is a helles bier, not a banana beer.
Variations on a theme --
Take this decoction recipe and use it to brew all of your favorite European Lagers!
If you want to make a festbier, take this recipe and add another 2.5 pounds of 2 row and half pound of munich.
For a Marzen , add 2 lbs 20 degree L munich instead of 1 lb 10 degree L, and add C40 instead of CaraPils.
For a pilsner, sub munich for acidulated malt and hop with 3 oz Saaz 10 minutes before boil ends. Also, add more CaSO4 and less CaCl
For a dunkel, use C40 instead of Carapils and use 3/4 pound chocolate malt instead of munich