In a medium saucepan over medium heat, heat the 1 tablespoon of oil then add the garlic. Cook for about 60 seconds, stirring continuously.
Add the cream, the lemon zest & juice, the salt, and pepper. Bring to a boil, then lower the heat and simmer for 15 to 20 minutes, until it starts to thicken.
Meanwhile, cook the pasta according to the directions on the package.
While the pasta is cooking, cook the florets in a pot of boiling salted water for 3 to 5 minutes, until tender but still firm. Drain the broccoli and run under cold water to stop the cooking. Set aside
When the pasta is ready, drain it in a colander and place it back into the pot. Immediately add the cream mixture and cook it over medium-low heat for 3 minutes, until most of the sauce has been absorbed in the pasta.
Pour the hot pasta into a large bowl, add the arugula, parmesan, tomatoes, and cooked broccoli. Toss well, season to taste, and serve hot.