1-Step 1: Start the Pasta Water Bring a large pot of generously salted water to a rolling boil. The water should taste like a well-seasoned soup; this is your only chance to season the pasta itself. Add pasta when you start cooking the mushrooms so everything finishes at the same time.

2-Step 2: Cook Pasta to Al Dente Cook the pasta according to package instructions, but subtract one minute from the recommended time. You want the pasta slightly underdone because it will continue cooking in the sauce. Before draining, reserve about 1 cup of pasta cooking water. This starchy liquid is pure gold for creating a silky, clinging sauce. Drain the pasta and set aside briefly.

3-Step 3: Begin the Mushroom Foundation In a large skillet, melt half the butter along with the olive oil over medium heat. The combination prevents the butter from burning while still providing that rich, buttery flavor base. Starting with butter and oil at the right temperature ensures even cooking throughout.

4-Step 4: Achieve Perfect Mushroom Browning Add the sliced mushrooms to the skillet in a single layer if possible. Crowding the pan causes steaming rather than browning, so work in batches if needed for larger portions. Cook the mushrooms until they release their water and it completely evaporates, then continue until they start browning on the edges, about 5 minutes total. Season with salt and pepper halfway through cooking; this draws out moisture and ensures even seasoning.

5-Step 5: Add Garlic and Remaining Butter Once the mushrooms show golden edges, add the minced garlic and remaining butter. Cook for 2 minutes until the garlic turns fragrant and golden alongside the mushrooms. Garlic cooks faster than mushrooms, so adding it later prevents burning and bitterness. The remaining butter melts into the hot mushrooms, infusing them with richness without requiring excessive amounts.

6-Step 6: Create the Creamy Sauce Add the drained pasta to the skillet along with about 3/4 cup of the reserved pasta water and the Parmesan cheese. Toss everything gently but continuously as the water reduces and thickens into a saucy glaze coating each piece of pasta. The starch from the pasta water emulsifies with the butter and cheese, creating a creamy sauce without any actual cream. If the pasta appears dry at any point, add more pasta water in small increments. The goal is a slick, juicy consistency where every strand or piece glistens with flavor. This technique mirrors what makes dishes like cacio e pepe so irresistibly smooth.

7-Step 7: Final Seasoning Adjustments Taste the finished dish and adjust seasoning as needed. Freshly ground pepper adds brightness, while a pinch more salt can deepen flavors. Remember that Parmesan adds saltiness, so taste before adding too much additional salt.

8-Step 8: Serve Immediately Remove the skillet from heat and serve your mushroom pasta immediately while hot. Garnish with freshly chopped parsley for color and a fresh flavor contrast. Offer additional grated Parmesan at the table for those who want an extra cheesy finish.