In a bowl, mix flour, sugar and cinnamon for the streusel topping. Cut chilled butter into small pieces and add to bowl.

Using hands, form crumbles by kneading butter pieces into the mix to make crumbly lumps.

Squish together crumbles yourself if it gets too "sandy." Chill in refrigerator for about an hour or until ready to make the rest of the cake.

Preheat oven to 180C/350F as you start the bottom cake layer.

Mix flour, baking powder and salt in one bowl.

In another large bowl, mix softened butter, yogurt, milk/cream, and sugar until it becomes smooth and creamy.

Add in the flour and baking powder mix to the yogurt mix. Mix until batter comes together enough to hold.

Dust flour on you hands and a cutting board, then remove dough from bowl and knead into a ball.

The dough should be fairly smooth. You can wrap and let sit until later or go ahead and roll it out for your cake.

When ready to roll, flour the rolling surface and roll dough into a shape that fits your baking pan (I used an 18cm tart form but you can use anything that works).

Press dough into your baking dish. I make the edges a little higher so it will hold the filling better, almost like a pizza!

Next, heat the milk and butter on low until the butter is melted.

Add in vanilla, semolina flour, cinnamon and honey. Stir well so the mixture becomes smooth (it's okay if there's still a few little lumps). Bring to a simmer, then turn off the heat and let soak for a few minutes.

If you have the tools, roughly grind the poppy seeds in batches using a mortar & pestle or food processor, etc. This help release the flavors of the seeds.

Pour the poppy seeds into the milk and flour mix. Stir until well combined. Add the raisins/walnuts here if using.

After the the poppy seed mix has cooled down a bit, mix in one egg. The mix can be warm, but it shouldn't be hot because you don't want the egg to end up cooking.

Spread the poppy seed filling evenly over the cake layer.

Lastly, top the filling with the strudel crumbles. Bake at 180°C/350°F for 25-30 minutes. Check after about 15-20 minutes to make sure the studels aren't browning to fast. If they are, lightly lay a piece of aluminum foil over the top.

The crumbles should be nice and golden when done! Remove from oven and let cool for 45-60 minutes.

Slice up and serve! If you like a touch more sweetness, drizzle with honey ;)