In a separate bowl whisk flour, salt, baking soda, ginger, nutmeg, pepper, allspice, and cinnamon together and set aside.
In a stand mixer with a paddle attachment, or a hand mixer with a large bowl, on medium speed beat the butter until smooth and creamy. Add the brown sugar and molasses and beat until incorporated. This will take about 2 min, making sure you scrape down the sides of the bowl on occasion. Add the egg and beat for another min.
Reduce the speed to low and add the dry ingredients. You want to mix until all of the dry ingredients just disappear. This will give a very soft dough. If there are some dry ingredient remnants in the bottom of the bowl mix those in by hand to avoid overmixing.
Divide the dough in half, wrap in plastic wrap, and place in the refrigerator for at least 3 hours.
Preheat the oven to 350°F/Gas Mark 4 with a rack centered in the oven.
Place the sugar in a bowl. Cut one of the portions of dough into 12 sections and roll each into a ball with your palms. Then roll the ball in sugar to completely coat it and place on the baking sheet.
Making sure each cookie has enough space to spread out take the glass and depress the cookies down until they reach a thickness of about ½ inch.
Bake cookies one sheet at a time for about 12-15 min, or until the tops feel set to the touch. Then remove from the oven. If the cookies are touching each other take a metal spatula and separate them while they are still hot. Transfer them to a rack after they have cooled down a little to finish cooling.
Repeat with the second batch.