Switch on the oven, then set it to 350 degrees F and let it preheat.
Meanwhile, take a medium bowl, place a banana in it, and mash it with a fork.
Add honey, egg, yogurt, and butter, and then whisk until well combined.
Add oats, flax meal, baking soda, and salt and stir until incorporated.
Take six silicone muffin cups, line each cup with a muffin liner and then fill them evenly with the prepared batter.
Prepare the crumb mixture and for this, take a small bowl, place all of its ingredients in it, stir until mixed, and then sprinkle on top of muffin batter.
Place the prepared muffins into the oven and then bake for 25 to 30 minutes until firm and the top turn golden brown.
Meal Prep: Let the muffins cool completely, and then wrap each slice in plastic wrap and foil.
Store each muffin in the refrigerator for up to 5 days or freeze for up to 1 month.
When ready to eat, thaw a muffin overnight in the refrigerator, microwave for 1 minute until warm, and then serve.