Before starting, preheat the oven to 425˚F.Wash and dry all produce. Arrange bacon strips in a single layer on an unlined baking sheet. Roast bacon in the top of the oven, flipping halfway through, until golden-brown and cooked through, 12-14 min.**Using tongs, transfer bacon to a paper towel-lined plate. Carefully transfer all but 1/2 tbsp (1 tbsp) bacon fat to a small heat-proof bowl. Reserve remaining bacon fat on the baking sheet.

Meanwhile, tear or cut ciabatta into 1-inch pieces.Quarter mushrooms. Peel, then mince or grate garlic.Peel, then cut half the shallot into 1/4-inch pieces (whole shallot for 4 ppl). Peel eggs.Whisk together mustard, vinegar and half the maple syrup (use all for 4 ppl) in a large, heat-proof bowl.

Add ciabatta to the baking sheet with reserved bacon fat. Season with salt and pepper, then toss to coat.Toast in the middle of the oven, tossing halfway through, until golden-brown, 8-10 min.

Meanwhile, heat a large non-stick pan over medium-high heat.When hot, add 1/2 tbsp (1 tbsp) reserved bacon fat, then mushrooms. Cook, stirring occasionally, until mushrooms are golden-brown, 4-5 min. Add half the garlic, then season with salt and pepper, to taste. Cook, stirring often, until fragrant, 30 sec.Transfer mushrooms to a plate.

Return the same pan to medium-high.When hot, add 1 tbsp (1 1/2 tbsp) bacon fat, then shallots. Cook, stirring often, until fragrant, 30 sec. Remove the pan from heat, then add remaining garlic. Cook, stirring often, until fragrant, 30 sec.Carefully transfer bacon fat and shallots to the large bowl with vinaigrette base. Season with salt and pepper, to taste, then whisk to combine.

Quarter eggs lengthwise, then season with a pinch of salt and pepper, to taste.Chop bacon into 1/2-inch pieces.Add mushrooms, spinach, half the croutons and half the bacon to the bowl with warm vinaigrette, then toss to combine. Divide salad between plates. Sprinkle cheese and remaining bacon over top. Top with eggs and remaining croutons.