Lemon Cream Rolls

Ingredients
For the Cream Filling:
1 egg
3 tablespoons of sugar
3 tablespoons of cornstarch
300 g milk
For the Dough:

200 g warm milk
3 tablespoons of sugar
1 teaspoon dry yeast
Lemon peel (zest of 1 lemon)
3 tablespoons of warm butter
1 egg
1/2 teaspoon salt
1/2 teaspoon vanilla extract
300 g flour (sifted)
Chocolate chips (optional)
For the Topping:

1 egg yolk
A little milk
Almond blossoms (optional)

Directions