Make Gingerbread Dough:

• In a large bowl using an electric mixer, beat the softened butter, packed dark brown sugar, and molasses together until light and fluffy.
• Add the eggs one at a time, beating well after each addition until fully incorporated.
• In a separate medium bowl, sift or whisk together the all-purpose flour, ground ginger, cinnamon, allspice, baking powder, baking soda, and salt.
• Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. The dough will be stiff. You may need to finish mixing briefly with your hands to fully incorporate the flour.  

Chill Dough (Crucial): Divide the dough into 2 equal portions. Form each portion into a thick disk, wrap tightly in plastic wrap, and refrigerate for at least 2 hours, or preferably overnight. Chilling is essential for rolling and cutting the dough.

Prepare for Baking:

• Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.
• Lightly flour a clean work surface. Remove one disk of chilled dough from the refrigerator.

Roll and Cut Cookies:

• Roll the dough out on the lightly floured surface until it’s about 1/8-inch thick.
• Using your mini gingerbread house cookie cutters (designed for mugs), cut out the required pieces: typically two roof panels, one front panel (with door/notch), and one back panel per house. Carefully transfer the cut pieces to the prepared baking sheets using a thin metal spatula, leaving about 1/2 inch space between cookies.
• Gather the scraps, re-roll once, and cut out more pieces. Repeat with the second disk of dough.

Bake: Bake one sheet at a time for 12-15 minutes, or until the edges are just golden brown and the cookies are set. Watch carefully as cook time depends on cookie size and thickness.

Cool Completely: Let the cookies cool on the baking sheets for a few minutes before carefully transferring them to a wire rack to cool completely. Cookies must be completely cool and firm before assembly.

Assemble Mini Houses:

• Prepare your royal icing according to package directions or your recipe. Place it in a piping bag with a small round tip (or use a small knife/offset spatula).
• Carefully pipe lines of royal icing along the edges of the cookie pieces to act as “glue.” Assemble the front, back, and roof pieces to form the mini houses. Hold pieces together gently for a few moments until the icing starts to set. Let the assembled houses dry completely until the icing is hard. (This may take several hours or overnight depending on icing consistency and humidity).
• Use extra icing for decorative details like “snow” or window panes, if desired.

Serve: Once the icing is completely dry and hard, carefully place the mini gingerbread houses onto the rims of mugs filled with hot cocoa, coffee, or tea.