Place a large pot of water over high heat. Cover and bring to a boil.
Heat the olive oil in a large skillet over medium heat until shimmering. Add the shallots and sauté until just translucent. Working in batches, add the mushrooms slices to the skillet and brown them on both sides. Don’t crowd the pan. Season the mushrooms with salt and set them aside.
Place the asparagus in the skillet and a generous pinch of salt. Sauté until just tender. Return the mushrooms to the skillet and add the butter, the garlic, and the thyme sprigs. Tilt the frying pan and spoon the butter over the vegetables. Transfer the veg to a bowl and set them aside.
Your water should be boiling by now. Liberally salt the water and add the pasta. Cook until al dente. This should take about 8-10 minutes.
400g (14oz) uncooked pappardelle
Deglaze the pan with the cognac and simmer until it reduces by half, this should only take a few moments. Add the Dijon mustard followed by the cream and the brined peppercorns, if desired. Simmer for 2-3 minutes
3 tbsp cognac, 1 tbsp Dijon mustard, ½ cup cream, 1 tbsp brined peppercorns **
Place the peppercorns in a mortar and pestle and coarsely grind them, set them aside.
1 tbsp dried peppercorns
Drain the pasta and place it in the sauce over low heat. Return the vegetables to the skillet and toss to coat and evenly disperse the vegetables. Divide the pasta across four bowls and garnish with the cracked peppercorns, a sprinkling of arugula, and Grana Padano. Serve immediately.
½ cup arugula, ½ cup grana padano
Notes
** Brined peppercorns are nice to have but can be tricky to find. If you can't find them, you can substitute them with additional coarsely ground dried peppercorns or omit them altogether.