Working in small batches, place brussels sprouts in feed tube of processor fitted with thin slicing disk; slice.
Melt butter with olive oil in large pot over medium heat. Add shallots; sauté until almost translucent, about 3 minutes. Add garlic; stir 1 minute. Add brussels sprouts; increase heat to medium-high and sauté until tender, about 8 minutes. Stir in 3 tablespoons pine nuts and lemon juice. Season with salt and pepper. Transfer to bowl. Sprinkle with remaining 1 tablespoon pine nuts and serve.
