Combine sugar, water, corn syrup, butter, and Mapleine; place over medium heat, stir until sugar dissolves.
Cook, without stirring, to hard crack stage (300° F.).
Remove from heat, quickly stir in soda and peanuts, stirring just enough to combine soda.
Pour quickly onto a well-buttered cooky sheet or shallow pan; stretch candy into as thin a layer as desired by pulling candy at opposite ends with two forks.
When firm, loosen from pan and turn candy over to prevent sticking to the pan.
When cold break in irregular pieces.
Notes
Makes about 1 pound peanut brittle. For a less foamy, more brittle texture, reduce soda to 1 teaspoon. If shelled unsalted peanuts are used, add ⅛ teaspoon of salt to the recipe.