Peel the potatoes (optional for Yukon Gold if you prefer a rustic texture) and cut them into equal-sized chunks for even cooking.
Place the potato chunks in a large pot and cover with water. Add a chicken bouillon cube for a savory depth of flavor (optional for non-vegetarian/vegan diets).
Bring the water to a boil, then reduce to a simmer and cook the potatoes until fork-tender, about 12–15 minutes.
Drain the potatoes and spread them out on a baking sheet or large plate. Allow them to cool to room temperature, then refrigerate for at least 4 hours (or overnight). This step converts some of the digestible starches into resistant starch, which helps manage blood sugar levels.
While the potatoes cool, preheat your oven to 400°F (200°C). Slice off the top of a garlic head, drizzle with olive oil, wrap it in foil, and roast for 30–40 minutes until soft and caramelized. Once cooled, squeeze out the roasted garlic cloves and set aside.
Reheat the cooled potatoes gently over low heat or in the microwave until warm.
Add the butter, almond milk, sour cream, roasted garlic (or garlic powder), and Parmesan cheese (if using). Mash the potatoes with a potato masher or use a hand mixer for a smoother texture.
Stir in the seasoned salt, onion powder, and fresh rosemary or thyme. Adjust the seasoning with additional salt and pepper to taste. Add more almond milk for creamier potatoes if needed.
Transfer the mashed potatoes to a serving bowl and garnish with parsley, chives, or a sprinkle of smoked paprika for a festive presentation.