Heat oven to 180C/160C fan/gas 4 and line two 12-hole muffin tins with 15 muffin cases. Melt the butter in a small saucepan or in the microwave, then leave to cool a little. Transfer to a large jug and stir in the yogurt, eggs and vanilla. Beat until combined.
Tip the flour, sugar, almonds, baking powder and 1/2 tsp salt into a large bowl. Stir to combine, then make a well in the centre. Pour in the wet ingredients and mix using a spatula or electric whisk until lump-free. It will be quite a runny mixture.
Spoon the mixture into the muffin cases so they are two-thirds full, using all of the mixture. Bake in the oven for 25-30 mins or until a skewer inserted into the centre comes out clean. Transfer to a wire rack to cool completely.
Beat the butter with half the icing sugar, then, once smooth, add the remaining icing sugar, the milk and vanilla extract. Beat again until fluffy and smooth. Reserving two large spoonfuls of the icing for the fondant cupcakes, halve the remaining icing and put into two bowls. Use a little of the pink food colouring to turn half of the icing pink, beating the icing until it changes colour. Use the purple colouring to do the same with the other half. Set all the icing aside at room temperature and cover the surface with cling film (or keep in the fridge overnight).
Roll out 250g of the fondant icing to a £1 coin thickness. Use the 3-piece cutters to stamp out three sunflowers. You will need to use each cutter three times (see step-by-step pictures). Scrunch pieces of foil into doughnut shapes and place in the muffin tin. Sit the flowers on top and leave to set for 30 mins. This will set the shape so the petals look more 3D. If you need more icing, roll out a little more until you have the right amount of flowers.
Using the reserved white buttercream, gently sandwich the flowers together. Dot a little buttercream in the middle of the biggest flower and put the medium-sized flower on top of it. Repeat with the smallest flower on top.
Pipe the buttercream roses and hydrangeas onto 12 of the cupcakes. Use the paintbrush to paint four stripes of pink food colouring from the bottom to the middle of a piping bag – this will create a dark pink outline for the roses. Drop the curved 2D nozzle into the end of the bag and snip off the end so that the tip is fully exposed. Pop the bag over a jug or large glass and fold over the top (this will make it easier to pile in the buttercream). Make sure all the air is out of the piping bag when you take it out of the jug, as this will ensure you pipe evenly. Starting in the middle of the cupcake, hold the bag directly above the cake and pipe a swirl in a clockwise motion, applying a steady pressure until you reach the edge of the cupcake. Repeat with another five cupcakes until you have six pink rose cupcakes. Set aside.
Use the paintbrush to paint four stripes of purple food colouring from the bottom to the middle of another piping bag, to create a dark purple outline for the hydrangeas. Hold the piping bag directly above the cupcake and pipe small star shapes to cover the entire surface (see step-by-step pictures).
Next, spoon the remaining white buttercream onto the remaining three cupcakes to completely cover. This will be the ‘glue’ for the fondant flowers. Carefully place each fondant flower on top of the cupcakes.
Sit the oasis in your basket or bowl. Cut the green tissue paper into small squares, laying a lighter piece over a darker piece, and fold in half, then half again, to create the leaves. Ruffle them up a little for a more natural look. Using a small sharp knife, poke a little hole in the bottom of your cupcakes and carefully insert a lollipop stick into each one. One at a time, push the bottom of the stick into the oasis – ensuring that you push the stick, not the actual cupcake, or you may damage the icing. Arrange the flowers so the three fondant flowers are near the middle, working outwards with the rest of the cupcakes until it starts to resemble a bunch. As the fondant flowers are quite heavy, roll out some small balls of leftover fondant to push under each cupcake base as support (see step-by-step pictures).
Slot the green tissue in between each cupcake so it surrounds them. Then lay the blue tissue paper over the pink paper and sit your basket carefully on top. Use sellotape to cover the entire basket in the tissue. Once it’s covered, do the same with the cellophane, if using. Keep in a cool place until presenting. The cupcakes will keep up to 4 days in an airtight container.