Cook pasta in large pot of boiling salted water until just tender but still firm to bite. Drain well. Meanwhile, melt butter in heavy medium skillet over medium-low heat. Add mushrooms and garlic; saute until beginning to soften, about 5 minutes. Add tarragon and saute until mushrooms begin to release some juices, about 2 minutes. Add whipping cream and Madeira; simmer just to blend, about 1 minute. Add pasta to sauce; toss to coat. Season with salt and pepper. Divide pasta between 2 plates. Garnish with parsley and serve. pasta 31