Heat oven to 375° F. Sift together flour, cocoa, baking powder and salt.
Beat butter in a large bowl until smooth and creamy. Add brown and granulated sugars and beat until light and fluffy. Beat in eggs, one at a time. Add vanilla.
On low speed, beat flour mixture into butter mixture. Stir in hot coffee. Fold in M&M's.
Drop batter by heaping tablespoonfuls onto ungreased baking sheets.
Bake at 375° F for 8 to 11 minutes or until set. Let cool slightly on baking sheets. Transfer cookies to wire racks to cool.