Preheat the oven to 375 degrees.
Line a 13x18 inch baking sheet with aluminum foil. Set aside.
In a large mixing bowl whisk together the flour and baking powder. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment combine the 4 eggs, sugar, oil and zest. Mix on medium speed until all the ingredients are combined.
Add in the dry ingredients and mix until a soft dough comes together, about 3-4 minutes. Do not over mix! The dough should be soft but stiff enough that it does not stick to your hands.
In a small bowl beat the remaining egg with a fork for the egg wash. Set aside.
Working with a handful of dough at a time, roll out the dough into a 1 inch thick rope.
Cut 5-6 inch pieces and shape each piece into an S shape about 2 inches apart. Gently press each cookie to flatten them slightly.
Brush each cookie with the egg wash. Bake for 18-20 minutes or until the cookies are golden brown.