In the bowl of a food processor fitted with the blade (or a blender if you don't have one), combine powdered sugar, dry milk powder and salt. Pulse to combine and cut milk powder into finer pieces, about 30 seconds. Set aside.
1 ¼ C Powdered Sugar, 6 ½ tsp Dry Milk Powder, ½ tsp Kosher Salt
In heavy bottomed saucepan, combine sugar, corn syrup, honey and water. Bring to a simmer and allow to cook for 4 minutes undisturbed.
½ C Sugar, 3 Tbsp Light Corn Syrup, 2 ½ Tbsp Honey, 2 ½ Tbsp Water
Clip candy thermometer to side of saucepan, ensuring the bulb isn't touching the bottom of the pan. Add butter and stir to combine. Cook until at least 235F and no more than 240F, then remove from heat. (See notes)
2 Tbsp Butter
Stir in vanilla and dry mixture with a silicone spatula until well combined. Pour out onto Silpat or parchment lined cookie sheet to cool. After about 15 minutes, the dough should be cool enough to handle.
½ tsp Vanilla Extract
Separate dough into 3 equal pieces. Color each piece (starting with 2-3 drops) of gel food coloring then knead to achieve desired and uniform color.
4-10 drops Gel Food Color
Separate each piece into two halves. Starting with one piece of each color, roll out into a long, thin strand, about ½" thick and 2' long. Stack the colors in the desired order, then gently smoosh (vertically) together all three pieces with your fingertips, being careful not to obscure the middle color.Using the palm of your hand, vigorously rub the top of the triad strand to flatten it and increase its sheen. Flip the piece over and repeat with your palm until mostly smooth.Repeat with other three strands. Using a bench scraper (or sharp knife) cut each strip into small triangles by alternating your tip left and right /. Continue until all pieces are formed.
Allow to cool completely, then store in single layers separated by parchment in an airtight container for up to 10 days.Enjoy!