Preheat oven to 225°F. Line two baking sheets with parchment paper.
Ensure the mixing bowl and whisk are completely clean and dry to help the meringue whip properly.
Beat egg whites on medium speed until foamy. Sprinkle in cream of tartar and salt; continue beating to soft peaks.
Add sugar a spoonful at a time while beating. Increase to medium-high and whip to stiff, glossy peaks.
Blend in peppermint extract and vanilla just until combined; do not overmix.
Paint thin stripes of red gel coloring inside a piping bag fitted with a star or round tip. Fill with meringue.
Pipe 1-inch kisses onto prepared sheets, spacing about 1 inch apart. Sprinkle lightly with crushed peppermint.
Bake for 75 minutes until dry to the touch, rotating pans halfway if needed.
Turn off oven, crack the door, and let cookies dry inside for 30 minutes. Cool completely on pans.