Step 1Generously grease 9-inch springform pan; wrap outside with foil (to avoid leakage). Set aside on baking sheet.
Step 2Melt butter in medium saucepan. Add sugar, water and cinnamon. Cook over medium-low heat, stirring until sugar dissolves, about 3 minutes. Stir in cranberries. Pour into pan and spread evenly. Set aside.
Step 1Sift together flour, baking soda and salt. Set aside.
Step 2Beat butter and granulated and brown sugars on medium speed until smooth and fluffy, about 1 minute. Add eggs, 1 at a time, mixing well after each addition. On low speed, add half of flour mixture. Mix until combined. Add sour cream and vanilla. Mix until combined. Add remaining flour mixture. Mix until smooth. Transfer batter to springform pan, spreading evenly over topping.
Step 3Bake at 350 degrees until golden brown, edges are just beginning to pull away from sides and toothpick comes out clean, about 45 to 50 minutes. Set on rack 10 minutes. Run knife around edge to loosen cake. Invert onto plate. Remove foil, ring and pan bottom. Replace any cranberries that fall. (Can be made up to two days ahead and kept at room temperature, covered airtight.) Cut into wedges and serve.