In a small saucepan, heat 2 tablespoons of extra-virgin olive oil over medium heat. Add 1 minced garlic clove and sauté for about 1 minute until fragrant but not browned. Remove from heat and allow to cool slightly before whisking in 3 tablespoons of balsamic vinegar, 1 teaspoon of granulated sugar, and a pinch of kosher salt and black pepper until smooth. Refrigerate while you prepare the rest of the salad.

Preheat your grill to medium-high heat, around 400°F. Slice 1 red onion into thick rounds, brush with olive oil, and season with salt. Place the onions on the grill, cooking for approximately 3-4 minutes per side until tender and charred. Meanwhile, season a 1-pound ribeye steak with salt and pepper, then grill for about 4-5 minutes on each side or until it reaches an internal temperature of 130°F for medium-rare. Remove both from the grill and let rest.

Once the steak has rested for about 5 minutes, slice it thinly against the grain for maximum tenderness. On a large platter, layer a generous amount of baby arugula or spinach as the base. Top with the sliced steak, grilled onions, diced avocado, halved cherry tomatoes, crumbled blue cheese, and fresh basil leaves.

Finally, drizzle the chilled balsamic dressing over the assembled salad, ensuring an even coating across the vibrant ingredients. Serve immediately, allowing the fresh flavors of this Grilled Steak Salad to shine. Enjoy this delightful and satisfying meal!