Before you start cooking: Grease a sheet pan with a knob of butter and dust it with 2 Tablespoons of flour. Preheat te oven to 340 °F.
In a large mixing bowl, crack 1 egg, add ⅓ cup sunflower oil and 1 cup granulated sugar. Mix with a hand-held kitchen mixer for 3 minutes.
In a separate bowl, whisk 1 ⅔ cups all-purpose flour, 1 cup ground poppy seeds, and 1 Tablespoon baking powder. Add the mixture to the beaten egg. Pour in 1 ⅓ cups milk and mix everything using a hand mixer on low speed until a semi-liquid batter is created.
Pour and spread the batter evenly into the prepared pan.
Bake for 30 minutes. To test for doneness, insert a toothpick into the cake center. The tooth stick needs to come out clean, or with a few crumbs stuck to the tooth stick, then the cake is finished.
Set the baked cake aside. Meantime, make a smooth lemon icing. To achieve this, mix 1 ½ cups icing sugar with freshly pressed 4 Tablespoons lemon juice. Drizzle the lemon icing over warm cake and spread it using a reverse side of tablespoon.
Allow the cake to cool completely in the pan. Slice and serve as a dessert or a coffee cake.
Notes
Makes 12-16 pieces.
Use whichever 10x15 inch (25x37 cm) baking pan with higher rims. The cake will rise while baked because of the baking powder's content.
The lemon icing is loaded with lemon flavor. It's a fantastic topping for this Czech-style poppy seed cake. Without this lemon icing, the cake wouldn't be complete. For the best result, use freshly pressed lemon juice.
EXTRA TIP: For more juiciness, add a handful of raisins to the poppy seed batter.