Preheat oven to 180°C. Grease and line the base and sides of two 20cm (base measurement) round cake pans with baking paper.
Use an electric mixer to beat butter, sugar, nutmeg, cinnamon, cloves and allspice until pale and creamy. Add the eggs, 1 at a time, beating well after each addition. Add the pumpkin and beat until well combined (the mixture may look slightly curdled at this stage).
Add the flour and buttermilk, in alternating batches, and stir until just combined. Divide between prepared pans and smooth the surface. Bake for 1 hour or until a skewer inserted into each centre comes out clean. Cool in pans for 5 mins before turning onto wire racks to cool completely.
Meanwhile, to make the cream cheese icing, use an electric mixer to beat the cream cheese and butter until smooth and creamy. Gradually add the icing sugar in batches, beating well after each addition. Beat in nutmeg, cinnamon, cloves and allspice until well combined.
Place 1 cake on a serving plate. Spread the top and side with half the cream cheese mixture. Top with remaining cake. Spread with remaining icing.
To make the praline, line a baking tray with baking paper. Place the sugar in a saucepan over medium heat. Cook, stirring, for 5 mins or until the sugar dissolves and caramelises. Remove from heat. Add pepitas. Gently swirl pan to combine. Pour over lined tray. Set aside for 10 mins to cool. Break into shards. Place around side of cake. Sprinkle small praline pieces over the cake.