TO MAKE THE CREPES:
Prepare the crepe batter: In a blender, combine crepe ingredients and blend until smooth. Transfer to a bowl and chill for 1 hour.
After chilling, grease two 10-inch nonstick skillets and place over medium heat. Staggering about 1 minute apart, add ¼ cup of crepe batter to each pan and quickly swirl to coat entire pan surface with a thin layer of batter. Cook until crepe begins to set and edges curl, 1-2 minutes, then carefully flip and cook for 1-2 minutes more. Transfer to a plate to cool.
Continue process, working between pans and stacking the cooked crepes on a plate to cool until you have 18 crepes total. Chill for 1 hour.
TO MAKE THE FILLING:
In a large bowl, mix filling ingredients until smooth.
TO ASSEMBLE THE CAKE:
Once crepes have chilled, grease a 9-inch springform pan with butter. Lay one crepe down, then top with ⅓ cup of the filling. Using a mini offset spatula, spread the filling into an even layer. Continue this process until all the crepes have been used. Cover with plastic wrap and refrigerate until the filling has set, about 4 hours.
Use a paring knife to release crepe cake from the springform pan. Garnish with confectioners' sugar, lemon zest and thyme leaves, then slice and serve.