Add milk and rosemary to a small lidded saucepan over low heat. Cover for 20 to 25 minutes, allowing herb to infuse. Remove rosemary sprig.
Meanwhile, bring a large pot of lightly salted water to boiling. Add gemelli. Cook 10 minutes, or as per package directions; drain and set aside.
In a large saucepan, melt butter over medium heat. Sprinkle in flour, whisking constantly for 2 minutes. Pour in infused milk, whisking until it comes to a boil. Simmer until thickened, about 3 minutes. Crumble in goat cheese, piece by piece, stirring until smooth. Add salt, figs, walnuts and cooked gemelli. Serve immediately.