For picky eaters, you can keep some spinach undressed and let them drizzle a bit of the warm bacon vinaigrette on their own plate so they can control how wilted the leaves get. If someone in your family prefers milder flavors, use a little less vinegar or swap in a white wine vinegar for a softer tang. To add a touch of sweetness without leaving the low carb lane, you can whisk 1/2 teaspoon of granular or liquid low-carb sweetener into the warm dressing. For extra richness, whisk in a teaspoon of butter at the very end of cooking the vinaigrette. If you don’t have baby spinach, torn mature spinach leaves work too—just remove thick stems so the salad still feels tender. You can also swap in baby kale or a mix of spring greens, keeping in mind that sturdier greens will wilt a bit less. For a little crunch, some families like to sprinkle chopped nuts (like pecans or almonds) on top, but that would be an optional fifth ingredient if you’re not strictly sticking to the four-ingredient idea. Food safety tips: Always cook bacon until it is fully crisp and reaches a safe internal temperature; avoid tasting partially cooked bacon. Be careful when adding vinegar and mustard to hot bacon drippings, as the mixture can bubble and release hot steam—keep your face back and use a long-handled whisk or spoon. Let the skillet cool slightly before moving it, and always pour hot drippings away from yourself to avoid splashes. If you have leftover salad, store it in a covered container in the refrigerator and eat within 1 day; the greens will be more wilted but still safe if kept chilled promptly. Reheat gently in a skillet over low heat, or enjoy cold if you don’t mind the softer texture.