1Move oven rack to lowest position. Heat oven to 400ºF. Lightly grease springform pan, 9x3 inches.
2Mix flour, butter and egg yolk. Press mixture evenly on bottom of pan. Bake about 15 minutes or until golden brown; cool.
3Reduce oven temperature to 350ºF . Mix cream cheese and seasoning mix in large bowl. Stir in eggs, one at a time, mixing well after each addition. Stir in Cheddar cheese and chiles. Pour over crust.
4Bake about 40 minutes or until center is set. Immediately spread with sour cream. Bake 5 minutes. Cool slightly. Cover and refrigerate at least 8 hours. Remove side of pan. Cut cheesecake into wedges. Serve with crackers.