Step 1: Preheat your oven to 350°F (175°C).
Step 2: In a large mixing bowl, cream together the softened butter, light brown sugar, and granulated sugar until light and fluffy, about 2-3 minutes.
Step 3: Mix in the crunchy peanut butter until fully combined, then add the eggs one at a time, followed by the vanilla extract.
Step 4: In a separate bowl, whisk together the salt, baking soda, and oatmeal. Gradually add this mixture to the wet ingredients, stirring until just combined.
Step 5: Fold in the M&M's, chocolate chips, and raisins (if using) until evenly distributed.
Step 6: Portion out the dough onto a baking sheet, leaving space between each scoop.
Step 7: Bake for 10-12 minutes or until edges are lightly golden. The centers may look slightly underbaked.
Step 8: Cool on the baking sheet for 5 minutes before transferring to a wire rack.