Combine butter and sugar in a medium bowl; using a wooden spoon, stir together vigorously until well combined. Add egg white, then whisk mixture for 30 seconds. Add flour and salt and whisk until combined. 

 

Transfer batter to a resealable plastic bag; cut a 1/3-inch opening in 1 corner of bag. Pipe batter onto prepared baking sheet in 2 1/2-inch-long strips, spacing 2 inches apart. Bake, rotating pan once, until edges are golden, 15 to 17 minutes. Transfer pan to wire rack to cool.

 

FOR RICOTTA: Bring a small saucepan of water to a boil. Using a sharp paring knife or vegetable peeler, cut zest from lemon in long strips, avoiding white pith. Very thinly slice strips lengthwise. Add strips to the boiling water and cook for 1 minute, then drain. Return saucepan to heat, add drained lemon strips, sugar and 3 tablespoons water. Cook mixture over low heat, stirring constantly until sugar is dissolved, then continue to cook until liquid is syrupy and zest is translucent, about 8 minutes more. Reserving syrup, strain candied zest through a fine-mesh sieve. Let syrup cool to room temperature. 

 

Finely chop enough of the candied zest to make 1/2 teaspoon. In a medium bowl, stir together cheese, 2 tablespoons syrup and chopped zest. Divide cheese into serving dishes. Top with remaining candied zest, cookies and a drizzle of syrup.