Does anyone know how to achieve this magenta colour on a sugar peonie? I’ve tried lots of combinations but the colour comes out flat. Thank you  M

get to the color as best you can through the gum paste then dust it with luster dust or flower/petal dust which is matte-- then you can steam it a couple seconds to hold the color on there --

Add a burst of life to them by using a slightly darker petal dust to enhance down inside the bloom and use much lighter petal dust to just glaze the outer edges of the petals.  As Kate said, stemming will take away the flat look, but if you want them slightly glossy, you can use edible glaze in spray form.  It would probably be too shiny for petals, though.

and to get the real light color tips -- take white or pearl dust or whatever lighter color and get some on the side of the dry paint brush -- knock off a bit so you don't overwhelm it --  and scrape a little off the side of the brush onto the edge of the petal -- you just get a bit off -- you probably already knew that -- but it's fun to do --

there are some nice magenta petal dusts.  You can also add some pearl dust.