Put eggs in a saucepan and add water to cover by at least 1/2 inch. Bring to a boil, then reduce heat slightly and boil for 2 minutes. Cover saucepan, remove from heat, and let eggs sit in hot water for 5 minutes for yolks that are cooked but still a bit jammy, or 10 minutes for yolks that are firm but still tender. Meanwhile, continue to next step.

Arrange bacon in a single layer in a large frying pan. Cook over medium heat, turning once or twice, until browned and crisp, 10 to 12 minutes. Transfer bacon to paper towels and set aside.

Drain eggs, return to saucepan, and fill with cold water. To speed up cooling, as the water warms up from the eggs, replace it with fresh cold water. Let stand until eggs have cooled to room temperature. Peel eggs and quarter them.

Whisk together olive oil, vinegar, mustard, honey, salt, and pepper in a large bowl. Slice bacon crosswise and crumble blue cheese.

For a tossed salad, add red onion and spinach to bowl with dressing and toss to coat, then add blue cheese, bacon, and hard-cooked eggs, gently toss salad again, and serve. Or, for a more dramatic presentation, place spinach on a large platter. Arrange bands of red onion, blue cheese, bacon, and eggs on top; drizzle with dressing; and serve.