Toast the shredded coconut in a dry pan over medium heat until the shredded coconut turn golden brown, fragrant, and crisp. Set aside.
Make the pandan infused coconut milk by blending together coconut milk and pandan leaves in a food processor. Then, strain out the pandan pulp using a strainer, cheesecloth, or coffee filter, making sure to squeeze out all the liquid. Measure the coconut milk, you should have about 95g. If you are under, just top it off with coconut milk.
In a large mixing bowl, add melted coconut oil, coconut jam, brown sugar, and cane sugar. Mix everything together until all the ingredients looks evenly incorporated. Then add in egg and beat the mixture until it looks light and fluffy.
In a separate bowl, mix together the pandan coconut milk, oat milk, and a small drop of pandan extract.
In a separate bowl, mix together the dry ingredients: mochiko, glutinous rice flour, baking powder, and salt.
Alternate adding some dry mixture and wet mixture to the sugar mixture. Please note that you may not need to use all of the milk mixture. The amount of liquid you needs depends on the type of glutinous rice flour/mochiko you use. Stop adding the wet mixture until the batter has the consistency of slightly thinner pancake batter. If the batter is too thick, add more oat milk, a tablespoon at a time.
Preheat the oven to 350F.
Prepare 6 baking cups on a baking sheet. Sprinkle a thin layer of the crumbled coconut cookie (optional). Fill the baking cups a little more than 3/4 the way full. Sprinkle about 2 tsp of the coconut cookie crumble and swirl into the batter (optional).
Bake it in the oven on the middle rack until the edges of the muffin starts to set but the center is still wet.
Remove the half baked mochi muffins from the oven and sprinkle the top with the shredded toasted coconut. Let it continue to bake until the top of the muffins has set and has started to turn golden.
Remove the mochi from the oven and let it completely cool before enjoying. Store the muffins at room temperature and enjoy them within 3 days.