Make cake. Carefully pour remaining untinted batter over baked flowers. Use spatula to evenly distribute batter in pan.
Bake 10 to 12 minutes. Cool in pan 10 minutes, then loosen the sides of cake from pan edge. Turn out of pan onto another piece of parchment paper. Gently peel off parchment from pan and turn cake back over. Starting at short end, roll cake so pattern shows on outside and cool completely.