Heat olive oil in a large saucepan over medium heat until simmering. Add the garlic, parsley, red pepper flakes, and 1/4 cup water. Cover and sweat, stirring occasionally, until soft. Add more water if necessary, to keep the garlic from caramelizing.
Add the cooked spaghetti to the garlic mixture and toss until combined.
Serve with a drizzle of olive oil and the minced tops of the spring garlic, if desired.