Preheat oven to 220 C. Drizzle a roasting tin with olive oil. Place the bacon in the roasting tin and cook in the preheated oven for 20 minutes.
Meanwhile, cook spaghetti according to package instructions.
During the last ten minutes of cooking the bacon, take tin out of the oven and sprinkle pine nuts over the bacon slices. Put the tin back to oven for the remaining 10 minutes.
When bacon is browned and crisp, take the tin out of the oven, add the drained spaghetti to the tin and toss thoroughly. Add the cheese and season with sea salt and black pepper. To serve, sprinkle with the tarragon and lemon juice.