Bring a large pot of water to a boil and pre-heat oven to 400 degrees F. Cook pasta 2 minutes shorter than recommended cook time. In a small pot, heat milk and cream until begins to simmer. Mix corn starch with 2 tablespoons water to create a slurry. Add slurry to the cream mixture to thicken, then season with salt, pepper and jalapeno. Slowly add 3/4 of the cheese into the sauce, whisking constantly. Add pasta to the mixture and let it sit for 5 minutes. Stir in yolks and place in a 9 x 9 greased baking dish. Bake in the oven for approximately 15 minutes or until bubbling and slightly caramelized on the top.