Stir together the two flours and 1 tsp of salt in a bowl. Gradually add enough water to form a stiff dough. Turn the dough out onto a lightly floured surface. Knead the dough until it is smooth, about 2 minutes. Shape the dough into a ball and cover it with a bowl. Let rest for 30 minutes.
Lightly dust 2-3 large cookie sheets with flour.
Cut the dough into 8 pieces. Work with one piece at a time, keep the remainder covered.
On a lightly floured surface, roll the dough into a 1/2 inch thick rope. Cut the rope into 1/2 inch pieces.
Using a small knife with a dull blade and rounded tip, press your index finger against the side of the blade and flatten each piece of dough, pressing and dragging slightly so that the dough curls around the tip of the knife to form a shell shape.
Spread the cavatelli on a prepared cooke sheet. Repeat with remaining dough.
If you are not using the pasta within an hour, place the pans in the freezer. When the pieces are firm, scoop them into a freezer safe plastic bag. freeze until ready to use. Do not thaw before cooking, put them straight into boiling water.
To cook the cavatelli bring at least 4 quarts of water to a boil in a large pot over high heat. Add the cavatelli and salt to taste. Cook stirring occasionally, until the pasta is tender yet still slightly chewy.
Meanwhile heat your favorite Sunday Gravy or Marinara sauce.
Drain the cavatelli, add the sauce and serve immediately. Top with grated Parmesan.