Microwave Peanut Brittle (My Mother-in-Law)

1 c. sugar
1/2 c. lite corn syrup
1/8 tsp. salt
1 1/2 c. roasted salted peanuts
1T butter
1 tsp. baking soda
1 tsp. vanilla

In a 2 qt. bowl, dissolve sugar, corn syrup and salt in the microwave on high for 5 minutes. Stir and add peanuts, microwave on high for 5 minutes more. Continue microwaving, stirring every 30 seconds, until lightly browned. Add last 3 ingredients and stir very fast. Spread thin over buttered cookie sheet (or line with parchment paper but NOT waxed paper because it will stick to the waxed paper), working quickly. Let stands 10-15 minutes and break into pieces.