In a large bowl, combine sugars pumpkin, oil and eggs. Beat until well blended. In a separate bowl, mix together flour, soda and salt. Add to pumpkin mixture and mix well. Stir in Original Chai concentrate and currants and blend together. Spoon into paper lined muffin cups filling two-thirds full. Bake 350*, 40 minutes or until done. Place muffins on rack to cool. Cool completely before icing. To prepare icing: beat cream cheese with butter until smooth. Beat in powdered sugar. Gradually add Original Chai concentrate until icing is smooth. Spread icing on cooled muffins.