Preheat your oven to 400°F. Place the potatoes in a large saucepan, cover with water, and bring to a boil. Once boiling, reduce heat and cook for about 5 minutes until the potatoes are just starting to soften. They should be slightly tender when pierced.

Drain the potatoes and return them to the pan. Add the olive oil, cover the pan, and shake it to roughen the potatoes. Arrange the potatoes in a single layer on a large baking sheet, making sure they don't touch. Bake for 1 hour, turning halfway through, until they are crispy and golden brown.

While the potatoes are baking, cook the bacon in a large skillet over medium-high heat for about 5 minutes, or until the bacon becomes crispy and the fat is rendered. Stir in the golden syrup until well combined.

Once the potatoes are done, toss them with the bacon mixture. Season with sea salt flakes and add fresh rosemary if desired. Serve right away.