Heat oven to 350°F. Line 12 mini and 12 regular-size muffin cups with paper baking cups. In large bowl, using whisk, mix flour, granulated sugar, 1/2 cup cocoa, the baking soda and salt. In medium bowl, using whisk, mix soymilk, canola oil, vinegar and 1 1/2 teaspoons vanilla. Pour wet mixture into dry mixture; beat with whisk until well mixed. Stir in chocolate chips. Fill each mini muffin cup with 1 level measuring tablespoon batter. Divide remaining batter among regular-size muffin cups.