In a small bowl, combine baking soda, cinnamon, and nutmeg. Set aside.

Spray a baking sheet generously with cooking spray, then set aside.

In a large microwave-safe bowl, add granulated sugar and light corn syrup. Use a spatula to stir until combined. The mixture will be very sticky and difficult to stir near the end; this is okay.

Microwave sugar syrup mixture on HIGH for 4 minutes, then stir. Return bowl to microwave and heat for another 3 to 5 minutes or until mixture turns a light golden color. Be careful not to overheat; a dark brown hue means the sugar has burned.

Remove bowl from microwave and quickly begin to add the following ingredients: vanilla, butter, the prepared spices from step 1, and the peanuts. Stir the mixture so that all the ingredients are combined. The mixture will lighten and may rise or appear "fluffy.”

Spray rim of the bowl with more cooking spray, then pour the brittle mixture on the prepared baking sheet. Working quickly, use a spatula or a spoon to smooth the peanut brittle out in a layer roughly the same thickness as the peanuts.

Let peanut brittle cool and harden for at least 1 hour. Once cooled and firm, use your hands to break the brittle into sizes of your choice (usually 2x2 inch in size)