01 - Place the halved baby potatoes in a large saucepan and cover with cold, salted water. Bring to a boil over medium-high heat. Reduce heat and simmer for 12–15 minutes or until fork-tender.
02 - Add the green peas to the pot during the last 3 minutes of potato cooking. Drain thoroughly and set aside.
03 - Melt the butter in a large skillet over medium heat. Whisk in the flour and cook, stirring constantly, for 1–2 minutes until a smooth paste forms.
04 - Gradually whisk in the whole milk, followed by the heavy cream. Continue stirring until the sauce thickens, about 3–5 minutes.
05 - Add salt, freshly ground black pepper, and ground nutmeg. Whisk until fully incorporated.
06 - Add the drained potatoes and peas to the sauce. Gently fold to coat evenly and cook for 2 minutes until heated through. Transfer to a serving bowl and garnish with fresh chopped parsley.