Butter a 9x13 inch pan generously.

In a large mixing bowl, whisk together 2 cups flour, cocoa powder, sugar, yeast, and salt.

Combine water and butter in a bowl or liquid measuring cup and microwave until the butter is mostly melted.

Add the warm water mixture along with an egg to your dry ingredients and mix well.

Incorporate additional flour gradually until the dough begins to come together in a ball.

Transfer your dough onto a lightly floured surface and knead for about 4-6 minutes until smooth and elastic.

Place your dough in a bowl, cover tightly, and let it rise in a warm place for around 10 minutes.

Roll out your dough into a large flat rectangle, about 15x10 inches.

Spread softened butter across the entire surface of the rolled-out dough, then sprinkle cinnamon and sugar over it.

Starting from one long side, roll tightly until you reach the opposite end and pinch along the seam to seal.

Cut your rolled dough into twelve equal pieces.

Arrange cinnamon rolls cut-side down in your prepared baking pan.

Cover tightly again and allow to rise in a warm place for about an hour until they double in size.

Bake your rolls in the preheated oven for approximately 25–35 minutes until they are no longer doughy inside.

Prepare your icing by whipping softened butter until light and fluffy, then gradually mix in two cups of powdered sugar.

Add hazelnut spread along with salt into your icing mixture and cream together thoroughly.

Spread the icing over your cooled cinnamon rolls generously and serve immediately.