Prepare a large bowl of ice water for an ice bath. Set aside.

Fill a large pot with salted water and bring it to a boil over high heat. Add the washed and trimmed green beans to the salted water and cook until bright green in color and crisp-tender, about 5 minutes. Drain the beans and then shock them by dumping them in the bowl of ice water to stop the beans from cooking any more. Drain the beans again and pat dry.

Cook the bacon in a large, heavy pan over medium-high heat until crisp. I prefer chopping my bacon first and then stirring it around in the pan to cook it for this dish, rather than frying the bacon in strips and chopping it up afterwards. Remove the cooked bacon pieces to a plate lined with paper towels using a slotted spoon, then pour out all but 2 tablespoons of the excess bacon grease

Add the onion to the pan with the reserved bacon grease and sauté until soft, about 4 to 5 minutes. Add the garlic and sauté just until fragrant, about 1 more minute.

Add the green beans and the pine nuts to the onion and garlic and toss to combine. Cook until heated through and pine nuts are toasty, about 5 to 6 minutes more, tossing frequently so the pine nuts don't burn. Return the bacon to the pan, add the lemon juice and toss everything to combine. Season with salt and pepper to taste.