In a small saucepan over low heat, melt the butter and chocolate chips, stirring until smooth. Cool. Add pecans; stir until well-coated. In a large bowl, combine the eggs, sugar, flour and vanilla. Fold in chocolate mixture.
Fill paper-lined muffin cups two-thirds full. Bake at 325° for 35-38 minutes or until a toothpick inserted near the center comes out clean. Remove from pans to wire racks to cool.
Note: This recipe contains no leavening. These are thick and yummy and not fluffy like regular cupcakes. ENJOY!