1
: Beat butter and cream cheese until fluffy; stir in flour. Cover; chill 1 hour.
2
: Divide dough into quarters. On floured surface, shape each quarter into a smooth ball. Divide first quarter into 12 balls. Press onto bottom and up sides of 1 3/4 inch muffin cups. Repeat with remaining dough.
3
: Combine Eagle Brand, egg and lemon juice; mix well. Stir in rind. Sprinkle blueberries into prepared cups; fill with Eagle Brand mixture.
4
: Bake in preheated 375ºF (190ºC) oven 20 minutes. Cool in pans; remove. Sprinkle with confectioners sugar, if desired. Store tightly covered at room temperature.