The Crispery Cookies and Cream crispy rice treat

Crispy Rice Treats Guide: Puffed Rice, Marshmallow and the Square

October 11, 2026

A crispy rice treat is two foams pressed together. One is puffed rice, a grain blown full of air in a hot oven. The other is marshmallow, sugar syrup whipped full of air and set. Melted together and pressed into a pan, they set into a square with no baking at all. This guide covers where the treat came from, why the texture changes as it sits, and how one bakery makes them by hand. To go straight to the shelf, shop crispy rice treats.

How rice gets crisp

The cereal at the heart of the treat was patented by the Kellogg Company. Eugene H. McKay's patent for a "cereal food," first filed in Great Britain in October 1928 and granted in the United States in 1933, describes the process. Rice is cooked with water, sugar and salt, often under steam pressure, then dried to a tough, rubbery state of about 15 to 30 percent moisture. It passes between rollers that press each kernel slightly without turning it into a flake. It is dried again until hard and brittle, to about 5 to 14 percent moisture, and finally heated to between 350°F and 600°F, where the kernels swell to several times their original volume and turn brown. The result, in the patent's words, is "crisp throughout" and "friable," with a cellular structure inside each grain.

That last step is a cousin of popping corn: water trapped in a dried grain turns to steam and inflates it. The popcorn guide covers the same physics from the corn side.

Who made the first treat

The treat's origin has a company version and a family version. Matt Lewis, writing in The Awl in 2017, laid out both. Kellogg's official position is that its Home Economics Department invented the Rice Krispies Treat in 1939. The company also told Lewis that it made marshmallow-free "Rice Krispie Bars" in 1932, and that a package printed in 1940 carried the first recipe with marshmallows.

The family version centers on Mildred Day, who worked for Kellogg from 1928 to 1933 and again from 1935 to 1936. According to her daughter, a Kansas City-area Camp Fire Girls group asked Kellogg for fundraising ideas, and Kellogg put Day on a train for Kansas City with specially made baking trays and a giant mixer. Kellogg confirmed to Lewis that Day attended a Camp Fire banquet in 1932 and served 1,600 Rice Krispie Bars, but said it could not attest to any role she played in developing the marshmallow treat. Either way, the recipe came out of a cereal company's kitchen.

Why the texture changes

Marshmallow is a wet foam. Food scientists writing in Acta Horticulturae in 2017 describe marshmallows as soft, foamy and porous, with a relatively high moisture content of about 17 to 21 percent by weight. They tie that moisture and porous structure to the risks that make marshmallow prone to sugar crystallization, foam collapse, and hardening or softening as it ages. In their storage trials, formulas with more glucose syrup took up moisture and turned mushy and sticky.

Puffed rice, by the numbers in the Kellogg patent, is dried to well under the marshmallow's moisture before it is ever puffed. A finished square therefore holds a moist foam against a dry, brittle grain, and the marshmallow half is the part prone to the hardening and softening the researchers describe. For a homemade batch, Kellogg's own recipe says to store treats in an airtight container for no more than two days at room temperature and calls them best on the day they are made. For a bakery square, follow the date the maker prints.

A treat made by hand

The Crispery's treats start from the same two foams. The Crispery, in Portsmouth, Virginia, is run by Judy Soldinger, a retired nurse, and her husband, Steve, who bought a small Long Island crispy treat business that was closing and brought it to Portsmouth, their home city. Virginia Living reported in 2024 that each treat is made by hand, that the marshmallow is made on site to the company's own formula, and that each square weighs six ounces and measures 3.5 by 3.5 inches. The magazine counted 50 flavors, with more in the works, and named Cookies & Cream a customer favorite, likening it to a giant, crispy sandwich cookie (shop The Crispery Cookies & Cream).

The flavors run from the classic toward the dessert case. Rainbow Sprinkles keeps to the birthday-party original (shop The Crispery Rainbow Sprinkles). Ginger Snaps and Key Lime Pie borrow from cookies and pie (shop The Crispery Ginger Snaps, shop The Crispery Key Lime Pie).

Making them at home

Melt low and stop early. Kellogg's recipe melts the butter over low heat, and culinary scientist Jessica Gavin says to take the pot off the heat the moment the marshmallows melt. Sugar cooked too long keeps firming as it cools, she explains, and is a common cause of hard treats.
Salt it. Gavin adds a quarter teaspoon of salt to a batch, and Deb Perelman's salted brown butter version on Smitten Kitchen uses a heaping quarter teaspoon of coarse sea salt.
Brown the butter for a nutty flavor, and watch the pot: Perelman notes that the gap between butter taking on color and burning is often less than a minute. Gavin adds a tablespoon of water back to the pan after browning, since browning drives off moisture and can leave the treats hard.
Press without packing. Spread the mixture into an even layer with a buttered spatula or waxed paper. Gavin's advice is not to press too hard: the more air left between the grains, the better.
Cool, then cut. Let the pan cool before cutting. Kellogg's recipe cuts a 13 by 9 inch pan into 2 inch squares.

Serving them

A square cut into quarters belongs on a dessert table beside cookies and bars from the sweet bakery shelf, or in a gift box with a few pieces of candy. Warmed briefly and set under a scoop of vanilla ice cream, a treat becomes a plated dessert. Crumbled, it makes a crunchy topping for pudding or a sundae.

The treat asks little of the cook: butter, marshmallows, cereal, a pot and a pan. What separates a great square from an ordinary one is restraint, low heat on the marshmallow and a light hand on the press, so the air that makes both foams worth eating stays in. The shop is at 263 Josephine Street in Cherry Creek, Denver, where visitors can ask staff questions, and products ship nationwide from theambrosianpantry.com.