Preheat oven to 350°F (180°C). In a medium bowl, whisk egg with maple syrup and oil. Stir in oats, pumpkin seeds, cranberries, and sesame seeds, if using. Generously coat a 12-cup muffin tin with oil. Divide oat mixture into 12 portions, about 1 heaping tbsp (22 mL) per muffin cup. Using the back of a spoon, press each portion into bottom of muffin cup.
Bake in centre of preheated oven until lightly golden around edges, 10-12 minutes. Carefully run a knife around edges. Let cool completely. To maintain their cute shape, it's best to unmould them as soon as they're cool, after about 5 minutes. Using a spoon, gently scoop and lift each coin out. These will keep well, stored in a single layer in an airtight container, for 1-2 days.