Preheat oven to 375 degrees. Line two (12-cup) muffin pans with paper liners.
CREAM CHEESE FILLING: In a medium bowl, using an electric mixer, beat together cream cheese, vanilla extract, and 1/2 cup sugar; set aside.
STREUSEL TOPPING: In a small bowl, combine 1/2 cup sugar, 1/3 cup flour, and 1 teaspoon cinnamon; cut in butter with a fork or pastry blender until large crumbs form; set aside.
PUMPKIN MUFFINS: In a large bowl, combine the remaining 3 cups flour, remaining 1 3/4 cups sugar, remaining 2 teaspoons cinnamon, cloves, nutmeg, baking soda, and salt.
In a medium bowl, whisk together eggs, pumpkin, oil, and milk. Stir egg mixture into flour mixture just until moist. (Do not over mix.)
Spoon half of the batter into prepared muffin pans, filling each cup 1/3 full. Dollop about 1/2 tablespoon cream cheese mixture into the center of each cup, and top each cup evenly with remaining batter. Sprinkle with streusel mixture.
Bake 20 to 22 minutes. Remove from pans; cool on a wire rack.