Sift together flour, cocoa powder, baking powder, salt, and cinnamon in a medium bowl. In large bowl, whisk together granulated sugar, butter, food coloring, vanilla, and eggs. Fold flour mixture into sugar mixture until smooth. Cover bowl with plastic wrap and refrigerate until chilled, about 30 minutes (it will still be soft). Heat oven to 375°F. Line 2 baking sheets with parchment paper. Place some cocoa powder in shallow bowl. Roll tablespoons of dough into balls, then completely coat in cocoa and transfer prepared baking sheets, spacing 3 inches apart.  Bake until cookies are slightly firm to the touch, about 12 to 14 minutes. Let cool on baking sheet 10 minutes. Repeat with remaining dough.