Classic Egg and Bacon Pie with Homemade Buttermilk Pastry

Wrap the butter in baking parchment and freeze for at least two hours, or ideally overnight, until it is completely solid.

Place the flour in a large mixing bowl. Coarsely grate the frozen butter directly into the flour, occasionally dipping the butter's end into the flour to prevent clumping. Pour in the buttermilk and use a cutlery knife to quickly bring the mixture together. Transfer to a work surface and use a bench scraper to fold the dough into a cohesive mass. Cut away one-third of the dough, shape both pieces into flat discs, wrap them tightly, and chill in the refrigerator while preparing the filling.

Place the chopped bacon in a cold frying pan and set it over medium heat. Fry for 5-6 minutes until the fat has rendered and the bacon is golden and crisp. Use a slotted spoon to transfer the bacon to a medium-sized bowl.

Melt a small knob of butter in the same pan over medium-low heat. Add the finely chopped onion and cook for 8-10 minutes until softened and lightly golden. Increase the heat slightly, stir in the grated garlic, and cook for another 2-3 minutes until fragrant. Add the onion mixture to the bacon bowl and let it cool for about 10 minutes.