The Mixed Media die is the Flourish one, MM set #2, from Tim Holtz/Sizzix.
The card base is a sheet of Pearl White, scored & folded in half.
I'd cut the die from a slightly less than A5 size pearl card, and I trimmed it further to give me some space for some embossed details on the card front.
After I'd trimmed it down, I used a piece of cardstock I'd coloured with oil pastels in Pinks, blues & purples, and fixed that behind the die cut area.
On the inside of the card, I marked where the panel would go, and then scored two lines either side of that with a scoreboard & stylus tool.

For this I used a board that has diagonal score lines on it.
I stamped the sentiment, from a Phill Martin set called Baroque Sentiments 2, in silver Encore pigment ink, and heat embossed using Silver detail powder. Final addition was three silk flowers, in colours to match the background paper. The Mixed Media dies are so useful for making fast, but good looking cards for any occasion, and have been a good investment.