In a large bowl, mix the flour, baking powder, and salt. Set aside.
Cream the butter, cream cheese, sugar, and agave nectar until light and fluffy. Add eggs, one at a time, beating well after each addition; add egg substitute, beating well after each addition. Beat in vanilla.
Stir flour/baking powder/salt into creamed mixture just until moistened.
Fold in cranberries.
Fill paper-lined muffin cups three-fourths full. Bake for 18-20 minutes or until a toothpick inserted near the center comes out clean. Cool for 5 minutes before removing from pans to wire racks.