Peel potatoes, cut into 2-inch chunks, and cover completely with cold water in a large pot. Boil for 12–15 minutes until a knife passes through with zero resistance. I learned the hard way that underdone potatoes turn gluey when you mash them, so I always test one piece first.

While potatoes cook, combine milk and sour cream in a small saucepan over low heat. Warm gently for 3–4 minutes—don't boil—until the mixture steams lightly. This step prevents temperature shock when you introduce cold dairy into hot potatoes.

Drain potatoes in a colander, then return to the dry pot. Set the pot over low heat for 1 minute to release any remaining water as steam. This drying step stops the mashed potatoes Thanksgiving creamy recipe from becoming soupy before you add any liquid.

Mash potatoes roughly with a hand masher while still in the pot, breaking them into thumb-sized pieces. Add olive oil and salt, then mash again for exactly 1 minute. I confess I used to over-mash here, creating paste instead of texture—stopping early creates the right balance.

Pour the warmed milk mixture in slowly while mashing gently on low speed. The warm dairy incorporates without shocking the potatoes into releasing extra starch that thickens the mix too much. Mash until lumps remain—these are intentional texture, not mistakes.

Stir in butter with a wooden spoon until completely melted and distributed, about 1 minute. Add black pepper, garlic powder, and onion powder, then taste and adjust seasoning. Because these powders bloom as they warm, the flavor deepens over the next few minutes even after you stop cooking.

Fold in fresh chives just before serving so they stay bright green and crisp-tasting. If you stir them in early, heat turns them dark and mushy, losing their fresh bite entirely.