In a large bowl, combine 2 cups flour, corn flour, sugar, yeast and salt. In a medium saucepan, heat milk, water and butter until warm. Stir milk mixture and egg into flour mixture. Mix in the remaining flour, 1/2 cup at a time, beating well after each addition. When the dough has pulled together, turn it out onto a lightly floured surface and knead until smooth and supple, about 6 to 8 minutes. Knead in the poppy seeds last, reserving 1 tablespoon for topping. Lightly oil a large bowl, place the dough in the bowl and turn to coat with oil. Cover with a damp cloth and let rise in a warm place until doubled in volume, about 30 minutes.
Deflate the dough and turn it out onto a lightly floured surface. Form into loaf and place in a lightly greased 9x5 inch loaf pan. Cover the loaves with a damp cloth and let rise until doubled in volume, about 40 minutes. Meanwhile, preheat oven to 375 degrees F (190 degrees C).
Bake in preheated oven for 30 to 35 minutes, or until golden brown and bottom of loaf sounds hollow when tapped. Remove loaf from pan, brush with melted butter and sprinkle with 1 tablespoon poppy seeds. Place on a wire rack to cool.