Place a metal cookie sheet in a 200℉ oven to warm. Mix corn syrup and sugar in a large glass bowl or measuring cup, then microwave on high for two minutes. Remove bowl from the oven and stir thoroughly. Microwave for two more minutes.
Stir in peanuts and microwave for three additional minutes.
Add 1 teaspoon butter, vanilla, and spices. Stir to combine and microwave for two additional minutes. During this time, remove the warmed pan from the oven and grease with 1 teaspoon butter.
After two minutes have elapsed, sprinkle baking soda over the peanut mixture. Mix vigorously, until the mixture becomes lighter in color and foamy.
Quickly pour the mixture over the warmed pan. Spread by tilting the pan back and forth.
Cool completely before breaking into pieces. Enjoy!
Notes
Avoid spreading with a spatula, as this will pop all the tiny bubbles that make the brittle airy and light.
Keep in mind the wattage of your microwave matters. The microwave used for this recipe is 1700 Watts (1.7 KW). Depending on your own microwave's wattage, the cooking time might need to be adjusted. Check out this post regarding Adjusting cooking times based on microwave wattage.
Although this is a pretty easy recipe, it requires you to move fast, so all the ingredients should be measured out and easily accessible before you get started.