To prepare Brussels sprouts, trim and cut X in stem.
Boil in salted water until a knife pierces easily, approximately 5 - 10 minutes. Drain and set aside.
In a large skillet, fry bacon until crisp. Remove crispy bacon onto a plate, and drain all but 2 tablespoons of bacon fat from pan.
Cook the onion in the remaining bacon grease until translucent.
Add the boiled, drained Brussels sprouts to the pan, and toss until hot.
To the sprouts, add back bacon and toasted pecans. Season to taste with salt and pepper.