Baking Cookies in a Hot Car: A Sweet Texas Summer Hack

Despite an early start, this summer's Texas heat is likely to persist through the end of October. So we might as well have some fun with it, right?

While there are many ways to joke about how ridiculously hot the Lone Star State can get, there's a bit of truth to some of them. While we can't change the temperatures, we can get a sweet treat out of it.

Can you bake cookies in a car?

Technically, yes — you can bake cookies in a car on an extremely hot day. However, it is best to stick to an egg-free recipe to minimize the risk of food poisoning. If you need another reason to try it: Your car will smell amazing!

How does it work?

This process relies on the greenhouse effect. Sunlight is shortwave radiation that enters the car through the windows. There, dark-colored interior surfaces, such as the seats and dashboard, absorb the energy and convert it into heat. This heat is then emitted as longwave radiation, which cannot pass back through the glass. As a result, the heat becomes trapped, causing the car’s interior temperature to rise significantly.

For cookies to bake, the temperature inside a car must reach at least 165 degrees, and that could take several hours. On a 90-degree day, the interior of a car can heat up to about 140 degrees in an hour, sometimes faster if you have a black interior, according to the National Weather Service.

While this temperature rise is dangerously quick for people and pets in an enclosed vehicle, it’s not fast enough to bake cookies, especially when compared to an oven, which can have cookies ready in just 10 to 15 minutes.

In a Texas summer, it doesn’t take much to turn your car into an Easy Bake Oven. To try the cookie experiment, follow these three steps:

1. Start by parking the vehicle in direct sunlight during the hottest part of the day, from noon to 5 p.m. Although the sun is at its peak strength around noon, daytime temperatures typically continue to rise into the late afternoon as the ground and air gradually heat the Earth’s surface.
2. Next, cover a baking sheet with aluminum foil, which serves as an excellent conductor of heat, then roll your egg-free cookie dough into small, quarter-size balls and space them out evenly on the sheet. To avoid burn marks, place a towel on the dashboard and set the baking sheet on top.
3. Lastly, position a thermometer beside the cookies to monitor the temperature from outside the car without opening the doors and releasing the trapped heat.

Cookies baked in a car tend to be softer and less browned than those baked in an oven because the lower temperatures inhibit the full caramelization of sugars, according to weather forecasting service WeatherBug.