Pre-heat oven to 425°F (220°C/200°C fan forced) and grease the muffin tins or line with patty pans.
Add plain and wholemeal flour, sugar and cinnamon to a bowl and mix.
In another bowl add the eggs, milk, yogurt and vanilla and mix well.
Melt the butter in a microwave proof bowl, but don't add it yet.
Peel, core and dice the pears.
Add the wet ingredients, melted butter and pears to the dry ingredients.
Mix until Just combined.
Spoon the batter into the muffin tins.
Bake for five minutes at 425°F (220°C/200°C fan forced).
Reduce the oven temperature to 375°F (190°C/170°C fan forced) and bake for a further fifteen minute or until golden.
Remove from the oven and serve immediately while still warm, or pop them aside for later for up to three days.