Stir 3 tablespoons kosher salt into 2 quarts of cold water in a large pot. Add yam cubes and bring to a simmer over high heat.

Lower heat to medium-low and simmer until yams are just tender but not falling apart, about 5–7 minutes. Drain thoroughly.

In the same pot, melt butter over medium heat. Whisk in brown sugar, lemon juice, cinnamon, and nutmeg until the mixture becomes a glossy, syrupy glaze.

Return drained yams to the pot, gently tossing to coat each piece in the citrus-scented glaze. Cook until bubbling and thickened, about 3–4 more minutes.

Transfer to a serving dish and sprinkle with chopped pecans or pistachios for a festive crunch. Serve warm as a holiday side dish.