Preheat the oven to 220°C (425°F/Gas 7). Combine all the dry ingredients together. Whisk together the buttermilk, oil, eggs and vanilla. Incorporate the dry ingredients, mixing together quickly. Add the pumpkin purée and stir in without overworking the dough.
Lightly grease 10 holes of a muffin tin and fill each halfway with the batter. Add 1 heaped teaspoon of cream cheese in the middle of each and cover with batter to the top of the mould. Bake the muffins for about 20 minutes until golden and a skewer inserted near the middle comes out clean.