Place the bacon in a cold deep pan. Set the pan over medium heat and allow to cook, letting the fat render from the bacon, until the bacon is done to your preference.
Remove the bacon and set aside. Pour the fat from the pan, leaving 1-2 tablespoons behind.
In the same pan you cooked the bacon, add the leeks and cook until soft. Add the garlic and cook until fragrant.
Add the rice and stir, cooking for a minute. Pour in the wine and cook until absorbed, stirring regularly.
Add the stock, one ladle at a time, cooking and stirring continuously until the rice is cooked to your preference. This will take 20-25 minutes.
Once the rice is cooked, stir in the mascarpone, Parmesan and bacon then season to taste.