Heat the oven to 400° and coat two baking sheets with cooking spray. In a small bowl, whisk together 2 3/4 cups flour, the baking powder, and the salt. In a stand mixer set on medium speed, beat together the butter and confectioners' sugar until fluffy. Reduce the mixer's speed to low, add the egg, lemon juice, and lemon zest, and blend until well incorporated. Add the flour mixture and blend until a soft dough forms. Add more flour, a tablespoon at a time, if the dough is sticky.
On a lightly floured work surface, roll out the dough until it's 1/4 inch thick. Use a knife or cookie cutters to shape the dough and place each cookie on a prepared baking sheet. Gather and reroll the dough as needed. Bake the cookies until their edges turn slightly golden brown, about 7 minutes, then transfer them to a rack to cool completely. Repeat with the remaining dough.
In a small bowl, whisk together the sugar, milk, corn syrup, and flavored extract until smooth. Divide the icing into separate bowls and tint each with food coloring. When the cookies have cooled completely, pipe or spread the icing onto the cookies. As you work, add more milk, 1 teaspoon at a time, to thin the icing, if needed. Let it dry completely before stacking or packaging the cookies.
For the ribbons, snip three thin strips of fruit leather. Use two to wrap around the cookie and the third to make a bow. If needed, use drops of water or icing to hold the pieces in place. Alternately, spread a layer of icing on each cookie and pipe a pattern in a contrasting color on top.