Preheat your oven to 425°F (220°C).

In a large pot, brown the beef chuck over medium heat until seared on all sides.

Add the chopped onions, carrots, and minced garlic; cook until softened.

Stir in the Guinness stout, thyme, and bay leaves, then let it simmer for about 30 minutes.

In a bowl, mix the all-purpose flour and unsalted butter until crumbly. Then add the egg yolk and enough cold water to form a dough.

Roll out the dough and cover the beef mixture in a pie dish, crimping the edges to seal.

Bake for 25 to 30 minutes, or until the crust is golden brown.