In a large pot, cover potatoes with water and bring to a boil and simmer until potatoes are tender, about 15 minutes. Drain and let sit until cool enough to handle.

On a large rimmed baking sheet, toss potatoes with the olive oil. Using the flat bottom of a mason jar or potato masher carefully press down on potatoes to smash flat.

Combine the melted butter and garlic, brush liberally on each smashed potato and season with salt and pepper.

Bake until the potatoes begin to brown and crisp, about 20 minutes.

Remove the potatoes from the oven and top with pesto and shredded cheese. Bake for an additional 5-10 minutes until the cheese has melted and the potatoes have achieved your desired crispness.