Preheat oven to 350°. Line 24 muffin cups with paper liners.
Sift together flour, baking soda, salt and cocoa powder. Set aside.
In a microwave-safe bowl, microwave morsels at 50% power 1 to 1 1/2 minutes or until melted and smooth, stirring at 30-second intervals.
In a large bowl using an electric mixer, beat the butter and sugar at medium speed until well blended. Scrape sides of bowl and beat in the vanilla. Add eggs, 1 at a time, beating just until blended after each addition. Add melted chocolate morsels; beat until blended.
By hand or with the lowest speed of an electric mixer fitted with a paddle, gradually add flour mixture to chocolate mixture alternately with sour cream, beginning and ending with flour mixture. Beat at low speed (or by hand) until blended. Gradually add hot coffee and stir until smooth.
Bake at 350° for 20 minutes or until a wooden pick inserted in centers comes out clean. Remove from pans to wire racks, and let cool completely