1 liter water
1 liter whole milk, 4% cream
160 grams grade 0 durum wheat flour
1 pinch salt
300 grams butter
4 eggs, lightly beaten
Mix together the water and milk and pour into a cast-iron skillet. Whisk in the flour and the salt. Bring the mixture to a boil, whisking continuously, until it just begins to boil. Then continue to stir occasionally with a wooden spoon for 20 minutes.
Meanwhile, melt the butter in a small double boiler until it begins to foam. Remove from the heat and transfer to a small pan with a pour-spout. Return to the heat and cook until the butter begins to burn.
When the 20 minutes have elapsed pour the beaten egg mixture into the cast-iron skillet. It will harden over the top. Then slowly add the butter. To serve, bring the cast-iron skillet to the table and hand out large spoons.