I teach a class in making molds for jewelry cabochons and findings, but the applications are the exact same.
I suggest you start with a two part silicone compound that is considered food-safe. Most simple silicone molding compounds can be measured out either by weight or volume. For smaller molds, like the bow you want, they often don't need de-gassing in a vacuum.
Smooth-On makes a series of food-grade silicones that will work well for culinary applications. This is directly from their site: "Smooth-Sil® 940, Smooth-Sil® 950, Smooth-Sil® 960, some Sorta Clear® Silicones, and the Equinox® Series are suitable for making baking molds and trays, ice trays, casting butter, chocolate and other applications used to produce foods. The ingredients in these products comply with FDA certification 21 CFR 177.2600."
You will also want to find something that has a flat back, to avoid having to make a two-part mold. You can use jewelry, candies, buttons... anything really, as long as it has a flat back - you can even sculpt your own design. The flat back gets glued down to foam core (because it's cheap and disposable), then a "wall" is built around it (you can use a plastic cup or small cardboard box), then use hot glue to seal the base. Then mix your silicone per instructions, pour and wait. It's really that simple.
This video is a good overview of the general process:
If you try it, I'd love to see the results.