Sieve all purpose flour , cornflour , spice powders , salt and baking soda together ,twice and set aside.
In a mixing bowl , add 2 eggs , brown sugar , granulated sugar and whisk well.
Add milk , pumpkin puree , vanilla essence , oil and whisk well all together so that everything mixes well.
Now take sieved dry ingredients in a bowl and slowly add wet ingredients part by part to the flour mixture.
With a spatula gently mix everything carefully such that no lumps are formed.
Finally , add ½ cup of walnut and stir into the cake batter gently.
Grease the cake tin / loaf pan and pour the batter.
Take a wide pressure cooker , add sea salt (crystal salt) into cooker and evenly spread salt. Keep a heat proof stand on sea salt and place cooker on a high flame on a stove top. This is similar to preheating in oven. Alternatively , you can bake cake in a preheat oven at 180 deg celsius and bake for 25 to 30 minutes.
After 6-8 minutes, salt to becomes sufficiently hot then immediately reduce the flame to low heat /sim and place cake tin inside the pressure cooker.
Remove gasket (rubber ring) from pressure cooker lid and securely close it.
Don't put vent weight( whistle) on the pressure cooker.
Cook on a low heat for about 35-45 minutes , till toothpick inserted comes out clean.
Remove the cake tin from pressure cooker and allow it to cool completely.
Invert the cake tin on a plate , tap it gently and remove the cake .
Wrap the cake with clingfilm and let it sit overnight before serving. The flavors meld well and tastes delicious when served on following day .
Serve cake at room temperature either for breakfast or with tea. Also you can serve slice of cake with scoop of ice cream.