01 - Preheat oven to 325°F. Grease and line an 8-inch square baking pan with parchment paper.
02 - Combine egg yolks and sugar in a large bowl. Beat until pale and creamy. Blend in melted butter and vanilla extract.
03 - Sift flour over the mixture; stir just until incorporated.
04 - Gradually whisk lukewarm milk into the batter until smooth. Set aside.
05 - In a separate bowl, beat egg whites with a pinch of salt until stiff peaks form.
06 - Gently fold beaten egg whites into the batter in three additions, keeping some lumps for best texture.
07 - Whisk together pumpkin puree, heavy cream, brown sugar, cinnamon, ginger, nutmeg, cloves, and salt until smooth.
08 - Pour the cake batter into the prepared pan and smooth the surface. Carefully spoon the pumpkin mixture evenly over the cake batter without mixing.
09 - Bake for 60 minutes, or until the center is just set and the top is lightly golden. Cake will remain slightly jiggly at the center.
10 - Cool completely in the pan, then refrigerate for at least 2 hours before slicing.
11 - Serve chilled or at room temperature, topped with whipped cream and a dusting of cinnamon or nutmeg if desired.