• Preheat the oven to 175°C. Prepare a loaf pan and baking paper.
• In a bowl cream the butter with sugars until fluffy. Take your time and mix them for 5 minutes. Add oil and mix for another 3 minutes. Add eggs and beat until smooth and fluffy.
• In another bowl mix flour, baking powder, grapefruit and lemon zest and poppy seeds. Add ⅓ of the flour mix and mix until the flour disappears. Add ½ of full fall milk (zakysanka) with a few drops of lemon, grapefruit juice and lemon juice. Mix until combined. Repeat the process until you add the flour mix as last.
• Pour it into the loaf pan and bake for 50-65 minutes or until the toothpick comes out clean. Take the pound cake out of the oven and let cool for 15 minutes. Take the pound cake out of the pan gently. While it's still hot, pour some grapefruit juice over it (just a few drops, not too much).

Icing

• When the pound cake is cool, mix in a bowl the juice from the other half of grapefruit with icing sugar. Add as much sugar and grapefruit juice as you need. If you want a thick white layer of icing, add more sugar. If you would like to have a thin layer, add more grapefruit juice.