Preheat the oven to 175 degree C/gas mark 4. Grease and line a baking pan with baking paper. Also line a muffin tray with liners.
Whisk together the flour, baking powder and salt in a bowl until well combined. Take another large mixing bowl and add the sugar, eggs, yoghurt and vanilla extract.
Using a hand mixer or wire whisk beat the mix till pale and well combined. While still beating, slowly add the flour bit by bit, mixing well after each addition and making sure no traces of flour is seen after the final addition.
Finally, pour in the oil and using a rubber spatula fold it into the batter. Do not mix it too vigorously. This may take a few minutes.
Transfer 3/4th cup of this batter into another bowl and cover the remaining batter with a cling film.
Into the smaller batch, add the food colouring and mix evenly, adding more colouring if necessary. Make sure the batter is evenly coloured.
Pour this batter into the prepared baking tray and bake in the oven for 10 to 12 minutes, or till a skewer inserted into the centre of the cake comes out clean.
Transfer to a wire rack and after five minutes turn it onto the rack and leave to cool. The cake needs to be completely cooled to be able to cut, so I put it into the refrigerator for about 15 minutes to speed up the process.
Using a heart shaped cutter (small enough to fit in a muffin hole) cut out around 8 to 9 hearts from the coloured cake. Keep aside
Pour around 1 tbsp of batter into each of the muffin holes and carefully place the cut out hearts into the centre of the batter, upright. It would help if all your hearts are facing the same direction.
Pour the remaining batter on top of the hearts slowly, so you do not disturb them, until about 3/4th full. If they have moved a bit, using a skewer or toothpick just place them upright.
Bake in the oven for 20 to 22 minutes or till the skewer inserted into the centre comes out clean. Transfer to a wire rack and cool completely before frosting.
For the frosting, using the paddle attachment of a mixer beat the cream cheese and powdered sugar until just smooth. Do not over do the beating or else the mix would become too loose and there will be no way to fix that.
Change to whisk attachment and pour in the vanilla extract and whipping cream. Whisk on high until stiff peaks form. Again if you overwhisk it, the mix would split and you need to start from scratch. So keep a close eye.
Transfer into piping bags (I used a rose tip) and pipe away.