In a small saucepan set over medium heat, warm the olive oil and garlic together, stirring occasionally. Cook for about 5 to 7 minutes, or until the garlic becomes soft and fragrant without browning. Remove from heat and allow to cool slightly.

Transfer the mixture to a blender and add the balsamic vinegar, granulated sugar, salt, and pepper. Blend until the dressing turns smooth and creamy. Pour into a jar or airtight container and refrigerate until needed. The dressing can be prepared up to one week in advance for convenience.

Preheat the grill to medium-high heat, giving it about 5 minutes to reach temperature. Lightly drizzle the onion slices with olive oil and season with kosher salt. Generously season both sides of the ribeye with salt and freshly ground black pepper.

Place the onions on the grill and cook for 2 to 3 minutes per side until they develop visible grill marks and soften slightly. Grill the steak, turning occasionally, until it reaches your preferred doneness — about 6 minutes per side for medium-rare, or until an instant-read thermometer registers 130°F when inserted into the thickest part.

Once grilled, transfer the steak and onions to a cutting board and let them rest for several minutes. Slice the steak thinly against the grain for tenderness.

Arrange the arugula or spinach on a large serving platter as the base. Layer the sliced steak on top, followed by the grilled onions, avocado slices, cherry tomatoes, and crumbled blue cheese. Garnish generously with fresh basil leaves.

Drizzle the balsamic-garlic dressing over the salad just before serving, or serve it on the side for guests to add to their liking. This steak salad is a perfect combination of smoky, tangy, and creamy flavors — a satisfying dish that’s both elegant and hearty.