Lemon Honey Vinaigrette: To a blender, add all the vinaigrette ingredients and blend until smooth. Store in an airtight container in the fridge.
Grilled Peaches: Clean and oil cooking grate. Prepare a charcoal or gas grill fire for direct grilling over medium-high heat (450°F). Brush peaches with butter. Place peaches directly over the heat for 3-5 minutes. If the fire gets too hot move peaches to a cooler side of the grill until you see desired grill marks. Remove from grill to cool.*
Spiced Honey Pecans: Add cast iron skillet to grill to get hot. Add all pecan ingredients (excluding butter) to the cast iron and bring them to a boil. Boil until the pan is dry, about 2 minutes. Transfer to a bowl and toss them with butter.
To assemble: Add mixed greens to a large platter and toss in ¼ of the vinaigrette. Layer on peaches, red onions, pecans, and goat cheese. Serve with a side of the remaining dressing and enjoy immediately.