Preheat your oven to 325°F and grease a 9”x13” baking pan with nonstick spray. In a medium bowl, whisk together the all-purpose flour, ground ginger, cinnamon, baking powder, and salt. Set aside. In a stand mixer fitted with the paddle attachment, beat the softened unsalted butter, brown sugar, and granulated sugar on medium-high until light and fluffy, about 3 minutes. Add the eggs one at a time, scraping down the sides and bottom of the bowl after each. Mix in the molasses until smooth. With the mixer on low, alternately add the flour mixture in three parts and the buttermilk in two additions (starting and ending with the flour mixture). Mix just until combined, then scrape down the bowl and mix for another 20–30 seconds. I find that careful mixing here keeps the cake especially tender.
Pour the batter into the prepared baking pan and smooth the top. Bake for 35 to 40 minutes or until a toothpick inserted in the center comes out with only a few moist crumbs. Let the cake cool completely in the pan before cutting into cubes for assembling the trifle.
In a medium saucepan, whisk together the granulated sugar, grated lemon zest, and lemon juice. In a separate small bowl, whisk the whole eggs and yolks, then incorporate them into the lemon mixture. Cook over medium-low heat, whisking constantly, until the mixture thickens to a pudding-like consistency, about 6–8 minutes. Remove from heat and whisk in the cold, diced unsalted butter a few pieces at a time until fully blended. Strain the lemon curd through a fine-mesh sieve into a bowl, cover with plastic wrap placed directly on the surface, and refrigerate until set, at least 4 hours. For brighter lemon flavor, I sometimes add a pinch more zest before chilling.
Using a stand mixer with the whisk attachment, beat the cold heavy whipping cream until stiff peaks form, then transfer to a separate bowl. In the same mixer bowl with the paddle attachment, blend mascarpone cheese, sifted powdered sugar, and lemon extract on medium speed until smooth. Gradually fold the whipped cream into the mascarpone mixture until well combined and creamy. Refrigerate until ready to use. I like to keep everything extra cold while making this so the whipped cream holds its shape beautifully.
In small mason jars or glasses, start by layering cubes of cooled cake (from Step 2), then spoon over some chilled lemon curd (from Step 3), followed by a layer of mascarpone whipped cream (from Step 4). Repeat the layers until you reach the top, finishing with a generous layer of mascarpone cream. Top with a gingerbread cookie or a sprinkle of extra lemon zest if desired. For extra flair, I sometimes add a tiny dollop of lemon curd on top before serving.