Grate the potatoes and onions into a bowl of water to prevent discolouring. When you’re ready to prepare the röstis, squeeze out all the excess water from the potatoes and onion and pat together to form discs.
Place a pan over a medium to high heat, add a little butter and, when hot, fry the röstis, one at a time, until crisp and golden on either side.
In a separate pan over a medium to high heat, fry the streaky and back bacons and pork rashers, then add the olive oil and fry the baby vine tomatoes until charred and blistered.
Bring a separate saucepan of water to a gentle boil. Add the vinegar and swirl with a spoon to create a whirlpool effect. Carefully crack the eggs into the water and poach until cooked to your preference.
Serve the röstis with the bacon and pork rashers and a few blistered vine tomatoes. Top with a soft-poached egg, spoon over the Hollandaise sauce, scatter with rocket and season to taste.
To make the Hollandaise sauce:
Add the eggs and cream to a double boiler and place over a saucepan of simmering water. Whisk vigorously until the mixture begins to thicken. Slowly add the clarified butter in a steady stream and continue to whisk until it is incorporated and the mixture has a silky smooth consistency. Add a squeeze of lemon and a pinch of salt and remove from the heat.