Jenny, I'm pretty sure I have the pumpkin custard recipe, but can't find it at the moment, I'll keep looking. I'm not sure if this is the dressing or not it doesn't have to be cooked, but here's what I found:

Lemon French Dressing

1 tablespoon cold water
1 teaspoon unflavored gelatin
1/4 cup boiling water or bouillon
1/2 cup fresh lemon juice
1/4 teaspoon Worcestershire sauce
1 teaspoon grated lemon zest
1 garlic clove
1/2 teaspoon dry mustard
Dash ground black pepper

In a container or jar with lid sprinkle gelatin over cold warer; then pour on boiling water or bouillon. Screw cover on jar and shake to dissolve gelatin.

Open jar and add remining ingredients; cover and shake well.

Serve at room temperature. If made ahead and refrigerated, this will jell. Put the jar into a saucepan holding hot water until dressing is liquefied.

Makes 4 servings.