Bring a large pot of salted water to a boil. Add spaghetti and cook until al dente. Reserve 1/2 cup of pasta water and then drain the pasta.
In a large skillet over medium heat, melt 1 tablespoon of butter. Add the minced garlic and cook until fragrant, about 1-2 minutes.
Pour in the white wine and let it simmer until reduced by more than half. Stir in the capers and lemon juice. Mix in the reserved pasta water, broth, and the remaining butter. Season with salt and pepper.
Add the cooked pasta to the skillet and toss until it is evenly coated with the sauce. Let the pasta sit for a few minutes to allow the sauce to thicken. Garnish with Parmesan and fresh parsley, if desired, and serve warm.