Can I make this dip ahead of time?
Yes. Prepare the dip in the baking dish, cover, and refrigerate up to 24 hours. Bake from cold, adding 5–10 minutes to the bake time.
What's the best way to roast garlic for this recipe?
Cut the top off a garlic bulb, drizzle with olive oil, wrap in foil, and roast at 400°F for 35–40 minutes until cloves are golden and soft. Squeeze the roasted cloves directly into the dip.
Can I substitute the cheeses?
Gruyère can be swapped for aged cheddar or Emmental. Parmesan is harder to replace but Pecorino Romano works if you reduce the amount slightly due to saltiness.
How do I know when the dip is done baking?
Bake until the top is golden brown and the edges are bubbling visibly. The center should jiggle slightly when gently shaken but not slosh.
Can I use frozen spinach instead of fresh?
Yes. Thaw frozen spinach and squeeze out excess moisture thoroughly to prevent a watery dip.