Bring a large pot of salted water to a boil. Boil the pasta according to package directions until al dente. Just before draining, reserve 2 cups of the pasta cooking water. Drain.: The kitchen fills with a warm starchy steam that hints at comfort ahead, and the sound of rolling boil signals readiness. Salting the water is non negotiable, because it seasons the fettuccine from the inside out, making the pasta itself flavorful rather than relying only on the sauce. When you test for doneness, look for a tender center that still has a hint of firmness, and when you lift a strand it should hold its shape without collapsing. Reserving from the pot feels counterintuitive, but that starchy water is the glue that turns melted goat cheese and butter into a glossy emulsion. A common mistake is draining all the water, leaving you with a lumpy, dry sauce; keep at least some on hand to adjust the texture.
Meanwhile, heat a large skillet over medium heat. Add the butter, garlic and crushed red pepper and cook, stirring often until the garlic is fragrant and beginning to caramelize, be careful not to burn the garlic. Add the herbs, mushrooms and kale, season with salt and pepper. Cook until the mushrooms are tender, about 5 minutes.: As the butter melts it foams and becomes a golden pool that carries the flavors, and the aroma of sizzling garlic should bloom quickly and intoxicatingly. Stirring often ensures the garlic softens evenly and gently caramelizes, which brings out its natural sweetness and reduces sharpness. The crushed red pepper should bloom in the warm fat, dispersing a subtle heat that you can feel on the back of your throat rather than overpowering the palate. Watch the pan closely, because burnt garlic will impart an acrid taste and cannot be rescued; if you see dark flecks, start over or remove them immediately.
When the pasta is ready, add it to the skillet along with the goat cheese and 1/2 cup of the reserved pasta cooking water. Toss well to combine, adding more pasta water if needed to thin the sauce. Remove from the heat and finish with a sprinkle of fresh basil and a squeeze of lemon. Enjoy!: The skillet transitions from fragrant to richly savory as the mushrooms release their moisture and begin to brown at the edges, producing a deeper, nutty aroma. The fresh herbs wilt slightly, releasing green notes that balance the umami, while the chopped kale softens and takes on a vibrant color. Use medium heat so the mushrooms can develop caramelized spots rather than briskly steaming, which would mute their flavor. Listen for gentle sizzling and keep turning the ingredients so they color evenly. A typical misstep is overcrowding the pan, which prevents browning and leaves the mushrooms limp and pale; if necessary, cook them in batches for the best texture.
When the pasta is ready, add it to the skillet along with the goat cheese and 1/2 cup of the reserved pasta cooking water.: At this moment the kitchen hums with anticipation as hot fettuccine meets the skillet's savory mixture. The heat and a small splash of starchy water coax the crumbled goat cheese into creamy ribbons that cling to the noodles, forming a sauce that glistens. Tossing vigorously helps the sauce emulsify, coating each strand so the flavors distribute evenly. If the sauce seems thick or clumpy, add more reserved water a little at a time until you reach a glossy, silky consistency. A common error is adding too much water at once, which dilutes flavor, so go slowly and adjust until it feels balanced.
Toss well to combine, adding more pasta water if needed to thin the sauce. Remove from the heat and finish with a sprinkle of fresh basil and a squeeze of lemon. Enjoy!: The final toss should create a harmonious union where the sauce clings to the fettuccine , flecks of herb scatter through, and the goat cheese appears as creamy pockets. The scent should be layered, with buttery warmth, garlic perfume, and an herbaceous bright top note from the basil and lemon. Taste and correct for seasoning with a pinch of kosher salt and pepper if needed. Serve immediately, because the texture is best right after assembly; leaving it too long can cause the pasta to absorb the sauce and dry out. Avoid reheating aggressively, which can break the emulsion and make the sauce separate.