Cut red potatoes into 1-inch chunks and place them in a large pot of salted water (use 1.5 tsp salt). Bring to a boil over high heat, then reduce to a simmer. While potatoes cook, slice green onions into thin rounds (keeping white and green parts separate for now), and cook bacon strips in a skillet until crisp, about 8-10 minutes. Transfer bacon to a paper towel-lined plate to cool, then crumble into ½-inch pieces once cool.

Simmer the potatoes for about 15 minutes, or until a fork easily pierces the largest piece—you want them cooked through but still holding their shape. I like to test a potato after 12 minutes rather than waiting the full time, since cooking times vary based on your stove and pot size. Once tender, drain potatoes in a colander and spread them on a clean kitchen towel or cutting board to cool for about 10 minutes; this helps them absorb the dressing better while staying fluffy.

While potatoes cool, whisk together mayonnaise, sour cream, and ranch dressing mix in a medium bowl until completely smooth and no lumps of seasoning remain. The combination should be creamy and cohesive. I find that using Hellmann's mayo really makes a difference here—it creates a richer, more velvety dressing base than other brands.

Transfer the cooled potatoes to a large mixing bowl and pour the dressing from Step 3 over them. Add the crumbled bacon from Step 1, the white and light green parts of the green onions, and black pepper. Fold everything together gently but thoroughly until every potato piece is coated with dressing. Taste and adjust seasoning if needed. Refrigerate for at least 1 hour before serving (or up to 24 hours), and garnish with the reserved green onion tops just before serving for a fresh touch.