Pre-soak a Römertopf or clay pot, top and bottom, in water for 10-15 minutes.
Place salmon steaks in the presoaked pot.
Combine melted butter, parsley, salt, garlic, lemon juice, and beer and pour over the fish.
Cover pot and place in a COLD oven. Set the oven temperature to 450°F (230°C). Cook for 30 minutes.
Remove the pot from the oven and pour off the liquid into a saucepan. Careful when you open the oven as steam will be trying to escape.
Return the pot to oven, without the lid, for an additional 5 minutes, to brown the salmon.
Meanwhile, heat the liquid and thicken it slightly with chosen thickener. Stir and continue heating until desired thickness is reached (should be a few minutes).