A French classic reimagined for better blood sugar control. Thinly sliced celeriac replaces potatoes in this rich, creamy gratin — all the comfort of a dauphinois with roughly 30% fewer carbs and a far lower glycemic index (GI ~35 vs ~80 for potato). Baked low and slow with a golden Gruyère crust.
Preheat oven to 170°C (340°F). Butter a large gratin dish (approx. 30×20 cm / 12×8 in). Rub the entire inner surface with the cut sides of the garlic cloves, then discard the garlic.
Peel the celeriac and slice as thinly and evenly as possible — 1.5 to 2mm — using a mandoline or sharp knife. Do not rinse the slices; the natural starch helps the gratin set.
In a large saucepan, combine the heavy cream, milk, nutmeg, salt, and pepper. Warm over medium heat until just below a simmer. Add the celeriac slices, stir gently to coat, and cook for 3–4 minutes until slightly pliable.
Transfer the celeriac and cream mixture into the prepared dish, spreading the slices into even, slightly overlapping layers. Pour over any remaining cream — it should come about halfway up the slices.
Scatter the grated Gruyère evenly over the top. Cover loosely with foil and bake for 40 minutes.
Remove the foil and bake for a further 15–20 minutes until the top is deep golden and bubbling at the edges, and the celeriac is completely tender when pierced with a knife.
Rest for 10 minutes before serving — this allows the cream to set and makes portioning easier. Excellent alongside roasted meat or fish.
Carbs come from celeriac — lower than classic potato gratin. Celeriac has a glycemic index of ~35, roughly half that of potatoes (GI ~80), so the glucose rise tends to be gentler and more gradual. Use your usual dosing method agreed with your care team to dose precisely. The high fat from cream significantly slows gastric emptying, which can cause a delayed glucose rise 2–3 hours post-meal rather than a sharp peak — monitor closely and log the result in your journal to refine your dosing strategy.
