I had bought some poppy seeds for my homemade bread, but never ended up using them, so I ended up making this cake with them:
To make the poppy seed mix, I used 100g poppy seeds, 45 ml milk, 30 g sugar and 20 g butter. Melt the butter in a small pot and add the milk, sugar and poppy seeds. Heat the mix for about 1 1/2 minutes, take it off the heat, and let it cool a bit. The original recipe calls for grinding the poppy seeds, but this was not possible with my normal kitchen mixer, so I used them the way they were. The main difference will be the texture of your poppy seed layer in the cake - ground poppy seeds will make a finer texture (obviously).
To make the cake batter beat 2 sticks butter (224g) with 175g sugar and 4 eggs until creamy. Add about 70 ml Baileys, some salt and vanilla sugar, two teaspoons baking powder and 280g flour.
Take 1/3 of the batter and put it in the bottom of the bundt form, put another 1/3 to the side. Add the poppy seed mix to the last 1/3 of the batter and add one egg. If you ground the poppy seeds you might have to add some extra Baileys here. Put the poppy seed dough in your pan, then top with the remaining 1/3 of the white batter.
Bake at 350 - 360 degrees for 50 - 60 minutes.