Preheat a grill or grill pan over medium-high heat. You want a hot surface that can sear and caramelize the sweet potatoes while developing a smoky flavor from the bacon.

Toss the sweet potato rounds with 1 tablespoon of olive oil and a pinch of salt. Lay them on the grill in a single layer and cook for about 3–4 minutes per side, until nicely charred and tender when pierced with a fork. Remove and set aside to cool slightly.

In a skillet, cook the chopped bacon over medium heat until it’s crisp and browned. Use a slotted spoon to transfer the bacon to a paper towel–lined plate to drain, reserving about 1 tablespoon of the bacon fat in the pan.

If needed, add the remaining 1 tablespoon of olive oil to the bacon fat and quickly sauté the red onion just until it softens and becomes a touch translucent, about 2 minutes.

Make the dressing: whisk together lemon juice, honey, Dijon mustard, the vinegar, a pinch of salt, and several grinds of black pepper. While whisking, slowly drizzle in 2 tablespoons of olive oil until the dressing is emulsified and glossy.

In a large bowl, combine the mixed greens, warm grilled sweet potatoes, crispy bacon, sautéed onions, and half of the crumbled blue cheese. Drizzle with the dressing and toss gently to coat the greens without bruising them.

Transfer the salad to a serving platter or individual bowls. Scatter the remaining blue cheese over the top and finish with a final drizzle of balsamic or a touch of extra dressing if desired. Serve immediately while the sweet potatoes are still warm for the best contrast between the melted cheese and crisp greens.