Place peanuts, sugar, corn syrup and salt in a 2 quart (2lt) microwavable bowl. Heat on high for 4 minutes. Remove the bowl from the microwave, stir and heat again for 3 minutes.

Meanwhile, line a cookie sheet with parchment paper and spray the paper with vegetable spray. Set aside.

Remove the bowl from the microwave, add the butter and vanilla and stir to combine well. Return the bowl to the microwave and heat for another 1.5 minutes.

Remove the bowl from the microwave and add the baking soda. As you stir together, the mixture will become foamy.  Pour the mixture onto the prepared parchment paper. Allow to cool for 30-60 minutes.

Once the peanut brittle is cool, break into pieces and store in an airtight container.