Preheat the oven to 180C/350F/Gas Mark 4.
Sieve the flour or flours, baking powder, baking soda, cinnamon or mixed/pumpkin spice and salt into the large bowl. Alternatively, put all of the above mentioned ingredients in a bowl and whisk gently with balloon whisk until mixed and aerated.
In a separate bowl mix together plant based yogurt, pumpkin puree, brown sugar, rapeseed oil and vanilla extract (if using) until well combined into a smooth mixture.
Pour the wet mixture into the dry one and gently mix until combined. Do not over mix!
Line muffin tin with paper cases and fill each three quarters full.
Put a teaspoon of plum jam on top of the batter and press in ever so gently. It will create a lovely glaze on top of your muffins as it bakes. Alternatively, fill your muffin cases only half way, spoon small amount of plum jam on top and cover up with some more muffin batter for that lovely jammy surprise in the middle. - For more filling/topping alternatives see post above.
Bake in preheated oven for approximately 25 minutes or until a toothpick inserted into the muffin comes out clean.
Cool on a wire rack and enjoy!