Prepare the Hot Mustard Sauce.

Combine dry mustard and vinegar in a small bowl.

Cover and let stand overnight.

In a small saucepan, combine the mustard-vinegar mixture, sugar, and egg yolk.

Simmer over medium-low heat, stirring constantly, until slightly thickened. Set aside.

Allow patty shells to defrost until workable, keeping them cool.

Saute sausage in a skillet until browned, crumbling it as it cooks.

Drain excess fat on paper towels and let cool slightly.

In a bowl, combine the cooked sausage and thyme.

Stir in an egg.

Let the sausage mixture cool.

Stack 4 patty shells on top of each other with wedges aligned.

Flatten the stacked patty shells slightly by pressing with the heel of your hand.

Roll the stack out into a 10-inch circle and trim the edges with a sharp knife.

Cut the circle into 8 triangles.

Place about 1 teaspoon of sausage filling on the wide end of each triangle.

Brush the tip of each triangle with a little water.

Roll each triangle into a crescent shape, starting from the wide end.

Place the crescents tip-down onto an ungreased cookie sheet.

Repeat with remaining patty shells and filling.

Roll out pastry scraps and form into additional crescents.

At this point, you can freeze the crescents on the cookie sheet, then wrap well once frozen.

Preheat oven to 400 degrees F (200 degrees C).

Bake for 15 minutes, or until the crescents are golden brown.

Serve the sausage crescents with the prepared hot mustard sauce.