Girl Scout cookies are not made from real Girl Scouts, but the first cookies they sold were made by real Girl Scouts. The sole recipe, published in 1922, was for sugar cookies, simple and fairly cheap.
But simplicity was likely necessary, as the scouts baked the cookies themselves. According to the Girl Scouts, this recipe was distributed to 2,000 scouts in the Chicago area who likely needed something quick, simple, and inexpensive to sell. The ingredients for a batch of six to seven dozen cookies clocked in at 26 to 36 cents, which in today’s money is less than six dollars. The scouts could sell a dozen cookies for about the same amount, making a tidy profit.
Things changed over time, and the Girls Scouts eventually abandoned the baking part to focus on the business part of cookie sales. Read the story of the first girl scout cookies at Atlas Obscura.