Preheat the oven to 375°F and line two baking sheets with parchment paper.
Melt the butter in a small saucepan over low heat.
Put the sugar in a mixing bowl, pour the melted butter over it, and mix well with a wooden spoon.
Add the egg and vanilla and mix until smooth.
Add the flour, baking powder and salt, and stir until just combined. Then fold in the chocolate and granola.
Drop tablespoon-sized dollops onto the sheets, leaving plenty of space between them because they really spread. Flatten each one slightly with your palm.
Bake for 8–10 minutes, until the edges are just turning golden.
Let the cookies cool on the sheets for 2 minutes, then move them to a wire rack.