Fill a large pot with salted water and bring it to a boil—this will take about 10 minutes, so start this first. While waiting, mince your garlic, slice the summer squash and zucchini into uniform 1/4-inch rounds (this ensures even cooking), zest your lemon, juice it, measure out your butter and goat cheese, and tear your basil into chiffonade. Having everything prepped before you start cooking means you can move quickly through the remaining steps without scrambling.
Once the water is boiling, add the pasta and cook according to package directions. While the pasta cooks, proceed immediately to Step 3—the pasta timing will work perfectly with the quick-cooking squash and zucchini.
Heat the olive oil in a large skillet over medium heat. Add the minced garlic and cook for about 1 minute until fragrant but not browned. Add the sliced summer squash and zucchini, stirring occasionally, and cook for 4-5 minutes until they're tender and lightly caramelized at the edges. I like to let the vegetables sit undisturbed for a minute or two between stirring—this creates nice golden color and develops deeper flavor.
Season the cooked vegetables with kosher salt and freshly ground black pepper, then reduce the heat to low. This gentle heat keeps the vegetables from breaking down further while you combine everything in the next step.
When the pasta is al dente, drain it (reserve about 1/2 cup of pasta water just in case) and add it to the skillet with the cooked vegetables from Step 3. Add the fresh lemon juice, butter, and goat cheese, tossing everything gently over low heat for about 1 minute until the cheese melts and creates a creamy, light sauce. The starches from the pasta water will help emulsify the butter and cheese if needed—add a splash if the mixture seems too dry. I prefer goat cheese for its tanginess, which brightens the sweet squash perfectly.
Divide the pasta between bowls or plates. Top each portion with a pinch of red pepper flakes, toasted pine nuts, fresh basil chiffonade, and grated Parmesan cheese. Finish with the lemon zest for brightness and a squeeze of fresh lemon juice if desired. Taste and adjust seasoning with additional salt and pepper as needed.