Combine the flour, oats, baking soda, and salt in a bowl. Set aside.
In a stand mixer, beat butter and sugar until smooth (about a minute). Add the peanut butter, egg, and vanilla and mix until combined. Slowly add the flour mixture until just combined.
Add the chocolate chips and pretzels and mix until just combined. Refrigerate until dough is firm, about an hour.
Preheat oven to 350 degrees and line baking sheet with parchment paper. Scoop 2 tablespoons of dough for each ball and roll dough in a ball. Press extra chocolate chips on top if desired.
Bake on the middle rack for 8-12 minutes or until cookies crack on top and are barely golden brown. Let cookies cool on the baking sheet for 5 minutes and sprinkle with salt while cooling. They will continue to cook as they cool.
Source: America's Test Kitchen