Preheat the oven to 200°C (gas mark 6, 180°C fan).
Line a large baking tray with baking parchment or foil.
Cut 450g thick-cut bacon into small, roughly 1cm pieces.
Spread the bacon in a single layer on the prepared tray, ensuring they're not overcrowded.
Bake for 15–20 minutes, stirring halfway through, until the bacon is golden brown and crisp.
Use a slotted spoon to transfer the hot bacon bits to a plate lined with kitchen roll to drain off excess fat, then leave to cool completely.
Once cool, crumble any larger pieces with your fingers.
Transfer to an airtight container and keep refrigerated for up to 5 days.