Begin by peeling and chopping 2 medium Russet potatoes into even chunks. Boil them in salted water for 15-20 minutes, or until they are fork-tender. Drain and let the potatoes cool completely before mashing until smooth. Alternatively, you can use about 2 cups of prepared mashed potatoes for a quicker start on your mashed potato flatbread.

In a large mixing bowl, combine the cooled mashed potatoes with 4 tablespoons of melted butter and 1 egg, mixing until smooth and well-blended. Gradually add in 1 cup of rice flour, 1/4 cup of corn starch, 1 teaspoon of baking powder, and 1/2 teaspoon of salt, stirring until a soft, cohesive dough forms.

Once your dough is well mixed, wrap it tightly in plastic wrap and place it in the refrigerator. Allow it to chill for about 30 minutes.

Preheat your oven to 450°F (230°C) while the dough chills. Remove the dough from the refrigerator and divide it into 8 equal pieces. Roll each piece into a ball, then flatten them gently to form a disk about 1/2 inch thick.

Line a baking sheet with parchment paper, then place the flatbreads on the sheet. Brush each top with melted butter and generously sprinkle with your everything topping mix. Bake for 15 minutes or until the tops are golden brown.