Preheat the oven to 200C/180C Fan/Gas 6. Line two large baking trays.
In a large bowl, or the bowl of a stand mixer, combine the peanut butter, brown sugar and melted butter until it has all combined - about 3 minutes on high speed.
Add in the eggs and vanilla and combine again.
Add the oats, baking soda and just a little salt. Stir together to reach a pasty consistency - it will be a little wet, but should be easy to scoop.
Place tbsp sized balls onto the trays, about 2 inches apart (4 to a medium/large tray max). Press down on each cookie a little.
Bake for approx 10 minutes, rotating the trays at halfway, until just golden brown at the edges. Let cool on a wire rack before serving!