Start by cooking the bacon in a large skillet over medium-high heat until crispy, about 8-10 minutes, then crumble it into 1/2-inch pieces and set aside. While the bacon cooks, bring a large pot of salted water to a rolling boil. Separate the scallion whites from the greens, chopping each into 1/4-inch pieces—you'll use the whites immediately and save the greens for finishing. Hard-boil the eggs if not already done, then peel and chop them into 1/2-inch pieces; set aside.

Add the red potato chunks to the boiling salted water and simmer for 12-15 minutes until just fork-tender but still holding their shape—you want them cooked through but not falling apart. Drain the potatoes immediately and let them sit undisturbed for 3 minutes to allow surface moisture to evaporate slightly. Transfer the hot potatoes to a large bowl and immediately toss with the apple cider vinegar and chopped scallion whites; this step allows the potatoes to absorb the tangy flavor while they're still warm. Let this mixture cool to room temperature, about 10-15 minutes.

In a small bowl, whisk together the mayonnaise, 1/2 cup drained horseradish, Dijon mustard, smoked paprika, kosher salt, and freshly ground black pepper until completely smooth and well combined. I like to taste this base before adding it to the potatoes so I can adjust the horseradish intensity to my preference—some people find the bite of horseradish quite strong, so you have room to dial it back or intensify it later. This dressing can be made while the potatoes are cooling.

Once the potatoes have cooled to room temperature, pour the horseradish dressing from Step 3 over them and gently fold it in along with the crumbled bacon and chopped eggs from Step 1. Stir until all components are evenly coated and distributed throughout. Cover the bowl and refrigerate for at least 2 hours—this chilling time allows the flavors to meld and the salad to develop better texture and cohesion.

Remove the salad from the refrigerator and give it a gentle stir to recombine any elements that may have settled. Taste and adjust seasonings as needed—you can add more salt, pepper, or a bit more horseradish if you'd like a sharper kick. I find that after chilling, the flavors mellow slightly, so don't be shy about seasoning adjustments. Transfer to a serving bowl and top with the reserved scallion greens and a garnish of extra crumbled bacon for visual appeal and an additional layer of smoky flavor.