PreparationMake dough: Stir salt into hot water until dissolved. Sift flour, baking powder, and sugar into a large bowl, then make a well in center and add lard and butter. Stir salted water into well with a wooden spoon, melting lard and butter, then stir flour into liquid, adding a little water if necessary, to form a soft and pliable dough. Knead dough on an unfloured surface until smooth and glossy, 3 to 5 minutes (dough will be soft and slightly sticky). Cover dough with a kitchen towel (not terry cloth). Make filling: Cook clams in wine in a medium saucepan, covered, over medium-high heat until just opened wide, about 5 minutes (discard any that remain unopened). Transfer clams to a bowl with a slotted spoon, then cook mussels in same liquid, covered, stirring once or twice, until opened, 3 to 5 minutes (discard unopened ones). Add mussels to clams and strain cooking liquid through a paper-towel-lined sieve into a bowl.
PreparationMake dough: Stir salt into hot water until dissolved. Sift flour, baking powder, and sugar into a large bowl, then make a well in center and add lard and butter. Stir salted water into well with a wooden spoon, melting lard and butter, then stir flour into liquid, adding a little water if necessary, to form a soft and pliable dough. Knead dough on an unfloured surface until smooth and glossy, 3 to 5 minutes (dough will be soft and slightly sticky). Cover dough with a kitchen towel (not terry cloth). Make filling: Cook clams in wine in a medium saucepan, covered, over medium-high heat until just opened wide, about 5 minutes (discard any that remain unopened). Transfer clams to a bowl with a slotted spoon, then cook mussels in same liquid, covered, stirring once or twice, until opened, 3 to 5 minutes (discard unopened ones). Add mussels to clams and strain cooking liquid through a paper-towel-lined sieve into a bowl.