Whisk 1 cup flour, baking powder, and salt in a medium bowl; set aside. Blend sugar and zest in a medium bowl with your fingertips until sugar is fragrant. Add butter; use a spatula to blend. Add egg, brandy, and vanilla; stir to blend. Add dry ingredients; stir until a moist dough forms. Transfer to a sheet of plastic; wrap tightly and chill for at least 2 hours and preferably overnight. Line a baking sheet with plastic wrap. Cut dough in half. Generously flour work surface (the dough is sticky). Working with 1 piece of dough at a time (chill remaining dough), dust top with more flour and roll out, turning occasionally to make sure it`s not sticking; roll out dough as thinly as possible, turning and dusting with flour as needed. Working with a zigzag pastry or ravioli cutter, a plain pizza wheel, or a long knife, cut dough into long strips, squares, diamonds, or shape of your choice. Place strips on prepared baking sheet; cover with another piece of plastic wrap. Repeat with remaining dough. Chill for at least 1 hour. Pour oil into a deep saucepan to a depth of 4″. Attach deep-fry thermometer to side of pan; heat oil to 350°F. Line a rimmed baking sheet with several layers of paper towels. Drop 4-6 pieces of dough into pan and fry until golden on both sides, 2-3 minutes. Using a slotted spoon or tongs and allowing excess oil to drip back into pan, transfer cookies to prepared sheet to drain. Pat tops with more paper towels to blot oil. While cookies are still hot, dust both sides with powdered or cinnamon sugar. Repeat with remaining dough, returning oil to 350°F between batches. Just before serving, dust Merveilles with more sugar.