Pasta with Browned Butter, Grilled Zucchini and Sweet Onions

Ingredients

• 2 medium zucchini (, sliced into rounds 1/4 inch thick)
• 2-3 sweet onions (, sliced crosswise, 1/4 inch thick)
• 3 garlic cloves (, minced)
• 1/4 cup basil (, chopped)
• 3 tbsp olive oil
• 1 tbsp lemon juice
• 2 tbsp butter
• salt and pepper to taste
• 1 lb dry spaghetti