With the rack in the middle position, preheat the oven to 350°F (180°C). Generously butter and flour a 10 to 12-cup (2.5 to 3 litre) Bundt pan.
In a small bowl, combine 1/4 cup (55 g) of the sugar with the poppy seeds, cocoa powder and cinnamon. Set aside.
In another bowl, combine the flour, baking powder, baking soda and salt.
In a third bowl, cream the butter, remaining sugar and the vanilla with an electric mixer. Add the eggs, one at a time, and beat until smooth. With the machine on low speed, add the flour ingredients alternating with the yogurt and milk.
Pour 1/3 of the batter into the prepared cake pan. Sprinkle with half of the poppy seed mixture. Cover with 1/3 of the remaining batter, then all of the remaining poppy seed mixture. Finish with the remaining cake batter.
Bake for 50 minutes or until a toothpick inserted in the centre of the cake comes out clean. Let cool for 15 minutes. Turn the cake over onto a wire rack. Let cool completely, about 2 hours.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.