Mix flour and yeast in a bowl. Add water, sugar, butter, and salt. Mix well and knead into a soft dough.

Cover the bowl with a kitchen towel and leave in a warm place until the dough has doubled in size. This usually takes 45 minutes to 1 hour.

Divide the dough into strands and braid the challah once it has risen. Brush with a beaten egg and sprinkle with poppy seeds. Let the dough rise for 15-20 minutes.

Preheat the oven to 180 degrees C, and bake the challah for 35-40 minutes until golden brown.