Preheat the oven to 400°F (200°C). Cut the top off the garlic head to expose the cloves. Drizzle with olive oil and wrap in foil. Roast for 30 minutes until soft.

In a saucepan, heat olive oil over medium heat. Squeeze the roasted garlic into the pan and mash it with a fork.

Add the heavy cream and chicken broth. Stir well and bring to a simmer.

Stir in lemon juice, lemon zest, salt, pepper, and oregano. Cook for 5 minutes until slightly thickened.

Cook spaghetti according to package instructions in salted water until al dente. Drain and reserve some pasta water.

Add the cooked pasta to the sauce, tossing to coat. If the sauce is too thick, add reserved pasta water to reach desired consistency.

Serve immediately, garnished with additional lemon zest if desired.