"Create a Mediterranean anti-inflammatory dinner recipe using 3 tablespoons olive oil, 10 ounces sliced cremini mushrooms, 3 large shallots or ½ small red onion thinly sliced, 3 large garlic cloves thinly sliced, 2 teaspoons fresh thyme leaves, salt and pepper, 2 cups vegetable or chicken stock, ½ cup heavy cream, 1 (1-pound) package potato gnocchi, 1 tablespoon Dijon or spicy brown mustard, and 2 big handfuls arugula (about 3 ounces or 4 cups). The recipe should be beginner-friendly and flavorful."