Preheat the oven to 200C.
On a large oven tray, toss the potatoes with the garlic cloves (bashed with the skin on), the olive oil and the rosemary and then season. Roast in the oven for 30 minutes
Add the marsala (or stock/water) and roast for a further 15-30 minutes. Until the potatoes are fully cooked and crispy on the outside.
While the potatoes are roasting, make the tomato sauce. Heat the olive oil in a small pot and add the sliced garlic, oregano and chilli flakes. Cook for a minute or so, then add the tomatoes. Season, bring to boil and cook for 15 minutes on a medium-high heat.
Blitz the sauce with a stick blender until smooth.
Serve the sticky potatoes with tomato sauce.