Blend the softened butter, 4 cups confectioners sugar, extract flavors, and milk until smooth and creamy.
Divide the sugar dough mixture into separate bowls (depending on how many different colors you're making).
Add a few drops of gel food color to the separate bowls and stir well to thoroughly mix each color.
Press approximately 1½ teaspoons of the butter mint mixture into each well of the silicone mold, making sure to press firmly enough to fill in all the detail and so there are no air pockets.
Place the filled silicone molds on a baking sheet and freeze for at least 1 hour, of up to 4 hours.
Gently remove the flower mints from the molds and place them in a single layer onto a parchment-lined baking sheet.
In a medium bowl, stir or whisk together the ingredients for the royal icing.
Add the icing to a small zip-top bag and snip off a very small corner of the bag.
Gently pipe a yellow flower center onto each butter mint flower.
Return the butter mints to a single layer air-tight container and refrigerate or freeze until ready to serve.