Heat 1 tablespoon of olive oil in a medium saucepan over medium heat. Add the chopped onion and crushed garlic. Season with a small pinch of salt and pepper. Cook for 4 to 6 minutes until the onion is soft and fragrant.

Add the roughly chopped English spinach to the saucepan. Cook for about 3 minutes, stirring, until the spinach has wilted and reduced in size.

Stir in the softened cream cheese and cook for 1 minute until it melts into the greens and becomes creamy. Remove the saucepan from the heat.

Add the grated parmesan to the warm mixture. Use a hand stick blender to blend the mixture directly in the pot until the sauce is smooth and even. Set the green sauce aside.

Meanwhile, bring a large pot of salted water to a boil. Add the penne pasta and cook according to the packet instructions until al dente.

Before draining the pasta, reserve about 1/3 cup of the starchy pasta cooking water. Drain the pasta and return it to the hot pot.

Pour the spinach sauce over the hot pasta. Add a little of the reserved pasta water and toss the pasta to make a glossy sauce. Add more pasta water if needed to reach the desired texture.

Gently fold in the fresh baby spinach leaves and the flaked hot smoked salmon. Stir just until the baby spinach wilts and the salmon warms through.

Divide the pasta into bowls and serve immediately.