Cut frog from background. Desaturate in preparation for turning to chocolate.

Filter the destaurated frog with plastic wrap filter.
Add a solid colour adjustment layer and flood fill it with a chocolate brown color. Use a clipping mask to clip the color to the frog layer. Blend on hard light mode.

For a more detailed explanation for how to turn anything into chocolate see
https://www.youtube.com/watch?v=IN41zkA0DtI

Cut boy from background and add a new plain gray background on a new layer.
Clone out cupcake.

Resize frog to fit in hand. Adjust chocolate frog color to match the chocolate on the face. Mask out lower areas of frog to show the childs fingers.
Add shadows for frog.

Add shadows for the boys body.
Add dirt on a new layer above the gray background and paint some colored dirt using colours from the boys clothes and various dirt brushes.
Add another layer above the boy and paint some more chocolate dirt on boy.
Make a frame by adding a new layer. Select all > Modify > border. Put in the border width and flood fill with color.
Using layer effects, bevel and emboss, add a reddish stroke and an inner shadow.
Add another layer on top of everything, flood fill with a chocolate color and blend on 20% soft light mode.