Pastry: Thoroughly butter 6 heat-proof soup bowls 2 to 3 inches deep and 6 inches in diameter. Place the flour and butter in a food processor and pulse to break the butter up into pea sized pieces. Add the yolks and 2 tablespoons of water and pulse to barely combine, adding the additional tablespoon of water if needed. Chill for 30 minutes. Roll the dough out to 1/8-inch thickness and line the buttered soup bowls, trimming any excess. Chill for 30 minutes then bake at 400 degrees F until pastry is set but not picking up any color, approximately 30 to 35 minutes.
Filling: Mix the butter and cheese together in a food processor. Place the eggs and sugar in a bowl and place it over hot water and whisk until very light and fluffy. (If using an electric mixer there?s no need to put it over hot water.) Fold in the sifted flour and baking soda followed by the melted butter/cheese mixture. Pour the filling into the pastry-lined bowls, filling them to the top. Bake at 400 degrees F for 35 to 45 minutes or until well browned, puffed up and a skewer stuck in the center comes out clean. Traditionally the top should be very dark, almost black.