LEMON STRIPS: Make up to two days and at least one day before.Using a pairing knife, carefully cut wide slices of rind from the lemon. Trim the white pith from the underside of the slices. Cut the lemon rinds into 24 thin strips. Curl each strip around your finger, brush with egg white, and dust liberally with sugar. Set the sugared strips on a clean baking sheet and place in a warm, dry spot overnight. Or place the sheet in a preheated 200 degree F oven for 3-4 hours, until dry.
CAKE: Combine the cake and pudding mixes in a large bowl, stirring to blend. Add the oil, eggs, water and lemon juice, stirring after each addition. Fold in the lemon zest and poppy seeds until just blended. Spoon the batter evenly into the prepared cupcake tins, about 3/4 full. Bake on the middle oven rack until the tops of the cupcakes spring back to the touch and are not too golden; about 15 minutes. Cool in the pan for 15 minutes, and then allow to cool completely on a wire rack before frosting or decorating.
FROSTING: Make while the cakes are cooling or the morning of the shower.Using a wooden spoon, cream the butter in a large bowl, Add the remaining ingredients, and continue creaming until the frosting is well blended and fluffy. Frost the cupcakes with a small spatula and decorate with the candied lemon strips.