I searched for sketches that could be done in one layer -- and I found these two -- both very similar:
My Favorite Things and at Clean and Simple
I layered some die-namics form My Favorite things to create the "sketch". The flower stamp is from Hero Arts and the SMILE is from Paper Trey. I colored it with Inktense pencils then, used watercolor to blend the inks. A couple of dots from Viva Décor pens. And done.
Pretty easy -- the hardest part was figuring out how to use the 2 dies to emboss the sketch I wanted.
The challenge at Less is More the subject of your One Layer Card should be Spring Flowers. I think this qualifies.
Also at the One Layer Simplicity the challenge is to use Watercoloring.
Thanks for looking. I hope you like it.