Preheat the oven to 350 degrees F. Line 2 baking sheets with parchment paper.
Mix the peanut butter, brown sugar, vanilla, cinnamon and eggs in a large bowl with a handheld mixer until smooth. Add the oats, cranberries and pepitas and mix until just combined. Use a 1/4-cup dry measuring cup or 1/4-cup ice cream scoop to scoop the dough onto the baking sheets, leaving at least 1 inch between scoops, making about 9 per tray. Flatten the scoops slightly with the back of a spoon. Bake until the cookies are starting to brown, 10 to 12 minutes.
Let them sit on the baking sheets for a couple of minutes to let them set up a little bit. Serve warm, or let cool completely, then store in an airtight container for up to a week. Also great for freezing and eating straight out of the freezer! Serve with Greek yogurt for slathering or dipping, if using.