Pressure cook the pumpkin cubes with the soaked dates with 1/4 cup water. Squeeze out the seeds from the cooked dates (if using dates with seeds). In a mixer jar, puree the pumpkin and dates. You'll get roughly 1 cup of thick puree.
Preheat the oven at 180 Celsius.
Mix the pumpkin date puree, oil, sugar, vinegar, yogurt, milk and vanilla extract in a bowl. Whisk well with a hand whisk or electric whisk until you get a smooth mixture.
Gently mix the sifted dry ingredients into the wet mixture. Pour into a well oiled 8" square tin, or line a muffin tin with paper cups and fill up to 3/4th (makes 12 muffins).
Bake at 180 Celsius until a tester comes clean; 30-40 minutes for cake and around 16-20 minutes for muffins.