Preheat the oven to 200C/180C fan.
Wrap the sausages with streaky bacon, rolling each one into a cosy blanket.
Place them onto a baking tray and cook in the oven for 20 minutes, until golden and crispy.
In the meantime, put a small pot onto a low heat and add 20g of the butter and the sage leaves.
Cook until the butter is melted and bubbling and the sage leaves have crisped up and darkened in colour.
Remove the sage butter from the heat and let it cool for a few minutes.
Then pour the sage butter into a bowl with the remaining cold butter and mix together vigorously until you have a smooth, spreadable butter with speckles of crispy sage leaves throughout.
Add a glug of olive oil to a frying pan over medium heat and fry your egg so it’s crispy around the edges.
To assemble the sandwich, spread your sourdough slices with sage butter, then put the pigs in blankets on one piece, followed by the fried egg.
Season with salt and pepper, then top with the second piece of sourdough and get stuck in.