Old Hippies Never Die, They just forget

Start by slowly melting the butter in a large sauce pan over medium/low heat. 

When the butter is all melted add the flour and salt and stir, cooking the flour and butter for about 5 to 6 minutes. Be sure to keep it moving so that the flour doesn't burn and it should start to take on a reddish brown color; this is called a roux. 

Take your roux off the heat while you scalled your milk.

When your milk is scalded, slowly add it to the roux, while whisking constantly, and return mixture to the heat.

When the mixture has thickened to the consistancy of heavy cream remove it again from the heat and slowly whisk in your beaten eggs. Keep it moving so that the heat of the white sauce doesn't scramble the eggs.

Return your savory custard to the stove and gently cook it on low heat for about 5-10 minutes, constantly stirring, until thick.

It should be pretty thick by this point, if not; keep cooking, but DON'T turn up the heat too high. 

Turn the heat down and fold in your mushrooms and breadcrumbs.

Remove the mixture from the heat and let it cool in the fridge. This will thicken it up even further, make sure it is easy to work with your hands,  and make sure that when you add the cheese in the next step, it doesn't melt right away.

Once it is cool, fold in your cheese and then form into balls, cylinders, or cones. Balls were easiest for me, but remember, the larger the size, the longer the final step will take. I have big balls, so they took a long time and I even had to bake them in the oven to finish them off.

Roll the balls in bread crumbs, really working them in, and set aside.

The final step (usually) is to deep fry them until golden brown and drain on brown paper.