Heat the oven to 300°F and line a large rimmed sheet pan with parchment.
Combine oats, pecans, pumpkin seeds, cinnamon and salt in a large bowl.
Whisk maple syrup, oil and vanilla, pour over the oats and stir until no dry pockets remain.
Spread on the pan and press firmly into an even compact layer about 1/2 inch thick.
Bake 35 to 45 minutes, rotating the pan after 20 minutes but not stirring, until the edges are golden and the center feels dry rather than wet.
Cool untouched on the pan for at least 35 minutes, then break into clusters and fold in optional dried cranberries.
