Bring a large pot of salted water to a boil over high heat. You need about 3 quarts.
Zest and juice your lemon and set aside. Finely mince your parsley and set aside. Wash and trim your broccoli into similarly sized florets.
When water is boiling, add in pasta and cook for times indicated on packaging.
When only 2 minutes remain on the pasta cook time, add in the broccoli.
Reserve 1 1/2 cups of pasta water, then drain the pasta and broccoli in a large strainer. Return the empty pot to the stove over low heat.
Add in your butter. When the butter is melted, add breadcrumbs, lemon zest, parsley, and a pinch of salt. Stir to coat. Cook for 1-2 minutes or until lightly toasted and browned. Remove to a bowl and set aside.
Return pot to heat and add in 3/4 cup of pasta water, cream cheese, milk, and lemon juice. Stir over low heat until cream cheese is melted. Taste and add another pinch of salt if needed.
Return the broccoli and pasta to the pot and stir gently to coat. Add in more pasta water if the sauce is too thick for your liking.
Serve with a generous scoop of breadcrumbs on top.
Notes
*One large juicy lemon is usually plenty, but you may need two if you have smaller lemons. You want between 2-3 tsp of zest, and about 3 tbs of juice.