Make sauce: Simmer strawberries in syrup with sugar, stirring, until sugar is dissolved, about 2 minutes. Cool to room temperature, then pur ée in a blender.
Assemble napoleons: Trim and quarter enough strawberries to measure 3 cups. Beat cream in a chilled bowl until it just holds stiff peaks.
Put 1 cookie on a plate and spread 1/2 cup whipped cream over it. Top with ‚ cup quartered strawberries and drizzle about 3 tablespoons sauce over them. Lean a second cookie at an angle over berries and lightly dust with confectioners sugar. Make 5 more napoleons in same manner.
Cooks' note: ·Sauce can be made ahead and kept, covered and chilled, 1 week.