Cook macaroni according to package directions. Meanwhile, in a large saucepan, cook beef and onion over medium heat, crumbling beef, until meat is no longer pink. Add garlic; cook 1 minute longer. Drain. Stir in next 8 ingredients. Bring to a boil. Reduce heat; simmer, uncovered, for 10 minutes. Drain macaroni; stir into beef mixture., Preheat oven to 375°. Transfer macaroni mixture to 2 greased 2-qt. baking dishes. Top with cheese and jalapenos. Cover and bake at 375° for 30 minutes. Uncover; bake until bubbly and heated through, about 10 minutes longer. Serve 1 casserole. Cool the second; cover and freeze up to 3 months., To use frozen casserole: Thaw in refrigerator 8 hours. Preheat oven to 375°. Remove from refrigerator 30 minutes before baking. Cover and bake, increasing time as necessary to heat through and for a thermometer inserted in center to read 165°, 20-25 minutes.