In the bowl of a stand mixer fitted with the paddle attachment, cream together the granulated sugar and the butter until light and fluffy. Add in the egg and vanilla and continue mixing until everything is combined.

In a medium bowl, combine the flour, baking soda, salt, and spices, and mix to distribute all ingredients evenly. With the mixer running on low, add in the flour mixture a little at a time and continue mixing until a smooth dough comes together.

Using a small cookie scoop, scoop the dough out and roll it into a smooth ball. Place on a silpat-lined baking sheet. Continue scooping and rolling until your cookie sheet is filled. Press your thumb or the handle of a spoon into the centre of each cookie. Fill the thumbprint in each cookie with about 1/2 teaspoon of the jam.

Bake the cookies for 14 minutes at 350°, rotating your cookie tray halfway through the baking time. Allow the cookies to cool on the baking sheet for a few minutes, then transfer to a wire rack to cool completely. Cookies will be very soft after baking, but will firm up as they cool.

Once the cookies are completely cooled, prepare the optional clove-spice glaze. In a small bowl or a glass measuring cup, combine the icing sugar, ground cloves, and second amount of ground cinnamon. Add the vanilla and milk and mix vigorously until all lumps have disappeared and you have a smooth glaze. Add more milk or icing sugar as necessary to make the glaze thicker or thinner. Drizzle over the cooled cookies in a zig zag motion and allow them to set for at least 20 minutes before serving.