Preheat oven to 350 degrees F.: The warm, thin air of a preheated oven creates even rise and consistent browning, so you will notice the smell of sugar beginning to caramelize once the cookies go in. If the oven is not fully heated, the cookies may spread unevenly, producing flatter shapes. A common misstep is placing trays in a not yet hot oven, which robs the cookies of their crisp edges, so allow your oven to reach temperature before baking.
In a large bowl, use an electric mixer to combine the shortening, sugar, nutmeg, baking soda, cinnamon and salt, beating until well combined. Beat in the eggs and molasses.: Expect the mixture to transition from granular to glossy as the shortening and sugar incorporate, releasing a warm spice aroma from the nutmeg and cinnamon . The texture should be smooth and slightly aerated, which helps with lift. If lumps remain, scrape the bowl and continue briefly. Avoid overbeating after adding the eggs and molasses , because too much air can lead to domed cookies that crack excessively or spread poorly.
Add in the flour a little at a time. If it becomes too tough to beat with the mixer, you can use a wooden spoon to beat in the rest.: As you fold in the all purpose flour , the dough will thicken and lose shine, becoming more pliable and slightly tacky. Watch for visual cues, the dough should pull away from the sides and form a cohesive mass. If you continue beating aggressively when the dough is thick, you risk developing gluten which makes cookies tough, so switch to a spoon as recommended and stop once combined.
In a small bowl, stir together the sugar and nutmeg.: Mixing the roll sugar gives a fragrant topping that sparkles on the surface, and freshly grated nutmeg will perfume the sugar, enhancing the first bite. The texture will be slightly grainy but aromatic. A slip I see often is skimming this step; skipping the spiced roll sugar reduces contrast and visual appeal, so do not omit it.
Shape dough into 1 1/2 inch balls. Roll balls in the sugar mixture. Place balls 2 1/2 inches apart on an ungreased baking sheet.: When shaping, you will feel the dough yield to gentle pressure, forming smooth spheres. Rolling in the spiced sugar coats each mound and ensures the crackled top. Leaving proper spacing is crucial, the cookies expand as they bake and touching pans will cause them to merge. A frequent error is crowding the tray, which prevents proper air circulation and results in misshapen cookies.
Bake for 10 to 13 minutes or until tops are cracked and edges are firm. Cool on baking sheet for a few minutes before transferring to a wire rack to cool completely.: During baking the aroma will intensify and you should see tiny fractures appear on the surface as the interior expands and the edges set. The edges should be firm and slightly darker, while the centers remain tender. Remove when the edges feel set but before the centers go hard, because carryover heat finishes the baking. A common mistake is leaving them too long, which robs the cookie of its contrast between crisp edge and tender middle.