Serves 4
Use a spoon to scrape the dark brown gills from the portobellos.

WHY THIS RECIPE WORKS:
Using pancetta and its fat in our Spaghetti with Mushroom and Tomato Sauce recipe compensated for the lean nature of the mushrooms and made our mushroom ragu meatier. Portobello mushrooms gave our dish bulk, while smoky porcini gave it concentrated flavor. Adding tomato paste and fresh crushed tomatoes to our mushrooms after they’d browned sweetened our sauce but also let the mushrooms shine through.

Makes about 6 cups
This recipe makes enough sauce to coat 2 pounds of pasta. Leftover sauce may be refrigerated for up to three days or frozen for up to one month. Eight teaspoons of gelatin is equivalent to one (1-ounce) box of gelatin. If you can’t find ground veal, use an additional ¾ pound of ground beef.

Makes 1 pound; serves 4 to 6
If using a high-protein all-purpose flour like King Arthur brand, increase the amount of egg yolks to seven. The longer the dough rests in step 2 the easier it will be to roll out. When rolling out the dough, avoid adding too much flour, which may result in excessive snapback.

WHY THIS RECIPE WORKS:
For a pasta dough that could be easily rolled out by hand (but still cook up into delicate, springy noodles), we added six extra egg yolks and a couple tablespoons of olive oil. In addition, we incorporated an extended resting period to allow the gluten network to relax and developed a simple, effective rolling technique.

Serves 12

One cup of plain yogurt thinned with ½ cup milk can be substituted for the buttermilk. Grate the onion on the large holes of a box grater. The ingredients in this recipe can be reduced by two-thirds to serve 4. For instructions on how to cook the pasta in less water, see Lots of Pasta, Less Water (related).

Serves 2 to 3 as a main dish, or 4 to 6 as an appetizer

For the most accurate measurements, weigh the potatoes and flour. After processing, you may have slightly more than the 3 cups (16 ounces) of potatoes recquired for this recipe. Discard any extra or set aside for another use. Besides the browned butter sauce, try our Gorgonzola Cream Sauce, Parmesan Sauce with Pancetta and Walnuts, and Porcini Mushroom Broth (related).