1/2 cup (4-ounces) unsalted butter
1 ¾ cup granulated sugar
1/2 cup whole milk
1/4 cup cocoa powder
1/2 cup creamy peanut butter
2 teaspoons vanilla extract
2 ½ cups quick cooking oats
1/2 cup toasted pecans, finely chopped
1/4 teaspoon salt
1/3 cup rainbow sprinkles