Cook the carrots using your desired method. I microwaved mine. Add the melted butter and mash with a potato masher or fork until nearly smooth. (I liked the texture it had when I left chunks of slightly unmashed carrot in the mix.)

Add 2 eggs, sugar, flour, baking powder, and vanilla. Mix well.

Separate the last egg, adding the yolk into the souffle. Whip the white until it is fluffy and forms stiff peaks.

Gently and carefully fold the egg white into the carrot mixture. Spoon into a 1 quart casserole or souffle dish that has been lightly greased or sprayed with butter-flavor cooking spray.