Here is a low-carb and keto muffin recipe that you can use as is or jazz them up by adding berries, extract flavoring or even, cream cheese icing. You can add some crushed almonds on top for some added nuttiness or some low-carb sweetener or cinnamon.
The choice is yours to add whatever flavors you want as long as you add keto-friendly ingredients. You will get the sweetness from the coconut milk but you can add erythritol or stevia to taste if you like your muffins a little sweeter. You will have experiment with how much to add.
The ricotta cheese helps to bind the muffin together.