Lightly spoon flour into dry measuring cups; level with a knife. Combine flour and next 5 ingredients in a bowl. Combine pumpkin, 3/4 cup brown sugar, milk, oil, and egg in a bowl; beat with a mixer at medium speed until blended. Stir in vanilla. Add flour mixture, stirring just until moist. Fold in cranberries. Pour batter into an 8 x 4-inch loaf pan coated with cooking spray.
Combine 2 tablespoons brown sugar, 2 tablespoons flour, and 1/4 teaspoon cinnamon in a small bowl. Cut in 4 teaspoons butter with a pastry blender or 2 knives until mixture resembles coarse meal. Sprinkle evenly over batter.
Bake at 350° for 1 hour or until a wooden pick inserted in center comes out clean. Cool in pan on a wire rack 10 minutes; remove loaf from pan, and cool completely on wire rack.