I highly recommend you invest in some silicone patty pans or a baking tray. It makes it so much neater and easier to handle the cakes.
Pre-heat your oven to 190 Celcius and get your patty pans organised.
If you're using individual silicone patty pans like me, find an oven proof dish that will hold them snugly without squashing them together too much. In my case I dont have a dish quite the right size so I filled in the extra space with a roll of baking paper. The idea is to make sure the patty pans don't bulge out with the weight of the mixture.
Using an electric beater or mixer, whip the butter until it's fluffy and lighter in colour. Then add the sugar and vanilla and keep beating until smooth.
Add the eggs and beat until there are no lumps.
Measure out the flour and baking soda and add them all at once. Only beat for a short while longer, just until combined, you don't want to over mix or the cakes will come out heavy.
Transfer the mixture into the patty pans. It's quite thick and sticky but don't worry because there's no need to be too neat.
Bake each batch for 5 mins then check on them. In my oven they take seven minutes but it may vary so keep an eye on them. They're done when they show some brown on the top and fall out of the patty pans smoothly.
Take the cakes out of the patty pans and cool them on a wire rack while you finish cooking the other batches.
Once all the cakes are baked, make sure they're properly cooled before moving on to the decorating.
Neaten up the edges of the cakes, trimming off any overly browned parts. Since the icing is quite tall, I like to take the very tall cakes and trim a little off the top.
Using a pair of teaspoons, put about 1/4 tsp of the jam onto the top of each cake. Try to use the firmer parts of the jam and avoid any more watery areas.
Ideally for the icing you should use a piping bag. You can make your own using a sandwich bag and filling it with the icing before cutting a small hole into one corner.
Pipe the icing onto the cakes in a swirl ending in a point in the middle. Finish them off by sprinkling the decorative hearts over the top.
Allow the cakes to stand for 10 minutes to let the icing firm up slightly before transferring them into the decorative patty pans.
Now your baby cakes are ready to eat. You can prepare them up to 12 hours beforehand, but don't refrigerate them as it will make the cake soggy.