Brownies became popular around the turn of the last century, when Bertha Palmer asked the chef at the the Palmer House Hotel in Chicago to create a cake-like dessert to be served in box lunches for ladies attending the 1893 Columbian Exposition. It had to be easier to eat than a slice of pie, but smaller than a piece of cake. The originals featured walnuts and an apricot glaze.
Here is the original Palmer House Brownies recipe:
1 pound semi-sweet chocolate
1 pound butter (4 sticks)
1 pound sugar (3 1/2 cups)
8 ounces cake flour (2 cups)
1 tablespoon baking powder
1 pound crushed walnuts (3 1/2 cups)
1/2 cup water
1/2 cup apricot preserves
1/2 teaspoon unflavored gelatin
Preheat oven to 300 degrees F.
Melt the chocolate and the butter together in a double boiler. (If you don’t have a double boiler, use a stainless steel bowl over a pot of simmering water.)
Mix in the sugar, flour, and baking powder until well mixed. Now add the eggs and mix until well mixed.
Pour mixture into greased 9 x 13 pan.
Sprinkle with walnuts and bake for 40 minutes. (Edges will become slightly crispy, and a toothpick in the center may not come out clean; it should be slightly gooey.)
Let cool 30 minutes.
Mix glaze ingredients in a saucepan. Bring to a boil for two minutes. While hot, spread a thin layer of glaze onto the brownies with a pastry brush.
At this point, you may wish to refrigerate or freeze them; it makes them easier to cut.