Dissolve yeast in apple juice and set aside until it bubbles. Combine remaining dough ingredients in mixer, adding yeast last. Mix until you have a soft dough. Divide dough in half.
Cover and let rise for 1/2 hour.
Meanwhile, sauté onion in oil until soft and golden. Add mushrooms and sauté another two minutes.
In a 4-quart pot, cook frozen vegetables according to package directions. Drain and add the sautéed vegetables, mayonnaise, eggs, and onion soup mix.
Using a hand blender, pulse vegetables into fine pieces (not creamy).
Preheat oven to 375 degrees Fahrenheit (190 degrees Celsius).
Roll out one piece of dough into a 12-inch (30-cm) circle. Cut into eight triangles. Place one teaspoon filling in the center of each triangle. Roll up, rugelach style, starting from the outer edge. Pinch ends tightly to make sure filling stays in. Repeat with remaining dough.
Place croissants on Gefen Parchment-lined cookie sheets and bake for approximately 20 minutes until golden.
Combine seasonings for garnish. While croissants are still warm, brush on seasonings with a pastry brush.
You can also freeze the croissants raw and bake them when you’re ready to enjoy (defrost one hour before baking).
For maximum freshness, wrap the croissants in cellophane before placing in burlap.
If you’re not sending the croissants freshly baked, make sure to include instructions to heat before serving.