Place the sliced parsnips in a saucepan, cover with cold water, and bring to a boil.
Reduce the heat and simmer until they are tender enough to be easily pierced with a knife.
While the parsnips are cooking, melt the butter in a small, light-colored pan over medium heat.
Continue to heat, swirling the pan occasionally, until the milk solids turn a golden brown and the butter smells nutty. Immediately remove from the heat and pour into a small bowl to stop the cooking process.
Once the parsnips are cooked, drain them thoroughly. Return the empty pan to a low heat and add the drained parsnips back in.
Stir the parsnips gently for about 4 minutes to cook off any excess water. You'll see steam rising as their flavor concentrates.
Remove the pan from the heat. Mash the parsnips until smooth, then stir in the browned butter, a pinch of nutmeg, and season generously with sea salt and black pepper.
Mix well and serve immediately.
Don't skip the step of drying the cooked parsnips in the pan. This removes excess water and is the key to a deeply concentrated, non-watery mash.
