Soak poppy seeds in milk for 2 hours or overnight in the refrigerator.
Preheat oven to 375°F; oil a Bundt pan.
Cream butter and sugar; Add eggs, one at a time, beating well after each.
Add poppy seeds with milk, sour cream, lemon juice and peel; beat well.
Add Sopaipilla Mix, beat well. Stir in just enough food color for light yellow batter, if desired. Pour into prepared pan.
Bake 55 to 60 minutes or until toothpick comes out clean. Remove from pan immediately after coming out of oven.