Cut margarine into flour, brown sugar, cinnamon and about 4 drops of food coloring (number of drops depends on how dark you want the red), in a medium bowl, using a pastry blender or crisscrossing 2 knives, until crumbly.
Heat oven to 400. Grease bottoms of 12 medium muffin cups or line with paper baking cups.
Prepare streusel topping; set aside.
Beat milk, oil, vanilla and egg in a large bowl. Stir in flour, sugar, baking powder and salt all at once, just until the flour is moistened (batter will be lumpy). Fold in blueberies. Divide batter among the muffin cups and top with 2 teaspoons of the streusel topping.
Bake 20-25 minutes or until golden brown. Remove from pan. These muffins are good warm or cool!