German Lemon Poppy Seed Cake (Mohnkuchen) — Irresistibly Moist

Let me introduce you to my German Poppy Seed Cake (Mohnkuchen) - it will take care of your poppy seed craving without any fuss. An easy poppy-seed cake made from a simple one-bowl cake batter with sweet and tangy lemon icing.

The crumb is deliciously moist, thanks to the yoghurt in the batter. The first bite has a satisfying crunch of thousands of poppy seeds and a subtle tangy hint of lemon that lingers on your tongue. The star is the simple lemon icing - turning this from a cake into a showstopper.

This is the cake I grew up with, here in Germany. I love making this cake because it is so simple - no separate poppy seed filling needed. The batter just comes together in one bowl and the lemon icing works every time.

This recipe has been on the blog since 2014 and every time I make it, the compliments follow. Although my son has very clear opinions - he says the cake simply does not work without the lemon icing. I have to agree with him!

What is Mohnkuchen?

Mohnkuchen is a traditional German poppy seed cake where the poppy seeds are the star ingredient. The name simply combines the German word for poppy seeds - "Mohn" - with the word for cake - "Kuchen."

When you visit Germany, you will come across all kinds of different Mohnkuchen. This recipe is made from a simple one-bowl batter with poppy seeds, yoghurt and lemon zest - it is the easiest version to make at home.

Another popular variation is Mohnstreuselkuchen - a combination of a classic Streuselkuchen base with a separate moist poppy seed filling baked on top. You may also have tried Mohnstriezel, a soft yeast bread with a sweet poppy seed filling rolled inside.

Ingredients you'll need

For the detailed instructions and exact measurements, please jump to the printable recipe card

For the cake you'll need butter and eggs at room temperature, sugar, ground poppy seeds, all-purpose flour (Type 405 in Germany, plain flour in the UK), baking powder (affiliate link), plain full-fat Greek yoghurt, a pinch of ground cinnamon (affiliate link) and the zest of half a lemon. I recommend using full-fat Greek yoghurt as it keeps the cake beautifully moist. If you can't find full-fat Greek yoghurt, sour cream works just as well as a substitute.

For the lemon glaze you just need powdered sugar (icing sugar in the UK) and fresh lemon juice. Simple as that!

Do I need ground poppy seeds?

No, you can use either whole or ground poppy seeds for this recipe. Ground poppy seeds are easier to digest as the grinding breaks down the outer shell. If you are using whole poppy seeds, I recommend soaking them in hot water for one hour before using - this achieves a similar effect and also helps them soften slightly in the batter.

Ground poppy seeds can be harder to find in the US. Your best bet is a Polish or Eastern European deli, or simply order them online - I use these ground poppy seeds from Amazon (affiliate link).

How to Make the Lemon Icing Glaze

The simple lemon glaze is what takes this poppy seed cake to the next level. It is the perfect finishing touch for a German lemon poppy seed cake - sweet, tangy and it sets beautifully on top of the moist crumb.

Sieve the powdered sugar into a bowl and whisk in the fresh lemon juice spoon by spoon until you have a thick, creamy consistency. If it gets too runny add a little more powdered sugar - if it is too thick add a few more drops of lemon juice. Spread over the completely cooled cake with a knife or palette knife and leave to set.

If you prefer a richer, creamier topping, a cream cheese frosting is a delicious alternative and gives this lemon poppy seed cake more of an American twist. I love the recipe from Sally's Baking Addiction for this.

How to serve this German lemon poppy seed cake

In Germany, this cake will traditionally be served with coffee or tea for "Kaffee und Kuchen". This is cake time in Germany and traditionally takes place in the afternoon (around 3pm). This is a naturally moist poppy seed cake thanks to the yoghurt in the batter - but if you fancy, why not serve it with a big spoon of whipped cream (Schlagsahne)?

Prepare in advance and store 

This is a great cake to prepare a couple of days in advance because it stays wonderfully moist for up to three days. Store it at room temperature in an airtight container and consume within 4 days.

Freezing instructions

This cake is great for freezing. Store individual slices in airtight containers or freeze it whole - it will keep for up to three months. Defrost at room temperature.