Whisk sugar and milk together in a small saucepan and bring to the boil
Take off the heat and add the butter, and stir.
Crush the poppy seeds to a moist powder in a mortar or with a spice grinder. Stir into the milk.
Crush the graham crackers and add to the mixture, and stir. Leave until needed.
Make the cake
Heat the oven to 180°C/350°F/Gas mark 4 (no fan assist).
Spray your bundt pan with a baking spray or butter it with softened butter.
Sift flour into the pan, and make sure you get every nook and cranny. Turn the pan upside down and tap it lightly against the counter to remove excess flour.
Put flour, baking powder, baking soda, and salt in a bowl and mix it with a whisk.
Beat cream cheese, sugar, brown sugar, and butter in your stand mixer until light and fluffy.
Scrape the sides and add the eggs one at a time; mix well after adding each egg.
Scrape the sides, add vanilla extract and orange zest and mix until combined.
Add the flour to the cream cheese mixture in batches of two. Mix about 10 seconds after each addition. In the end, scrape the sides and mix 5 seconds more.
Pour half the batter into the pan. Use a wetted spatula to even the top of the dough.
Add the poppy seed filling on top of the dough. Leave about ¾ inch room to the edge.
Pour the rest of the dough on top and tap the pan against the counter to remove air bubbles.
Bake for an hour or until a toothpick comes out cleanly when inserted into the middle of the cake.
When done, take out of the oven to cool on a wire rack for fifteen minutes in the pan. Then invert the pan onto the wire rack. Leave to cool completely.
Make the glaze
Put a small saucepan onto medium heat and let it get warm.
Add poppy seeds to the pan and let med toast for about a minute with constant agitation. Pour the toasted sesame seeds into a small bowl.
Put the pan back on the heat and melt the butter. Let it brown for about 8-10 minutes. Swirl it around so that it doesn't burn. Pour the butter into a bowl through a fine-mesh strainer to avoid the sediment.
Add confectioner's sugar, orange zest, orange juice, and milk to the butter. Mix until you have a completely homogeneous mixture, then stir in the toasted poppy seeds.
Working quickly, pour the glaze over the cake and let it slide down the sides.
Let the glaze get hard before you serve the cake. It can stay nice and moist for a few days if wrapped in foil or plastic wrap.