Preheat the oven and keep the temperature at 350℉.
Prepare a muffin tray and grease it.
Mix orange juice, vanilla extract, eggs, yogurt, sugar, and butter until well combined.
Sift in oats, baking soda, all-purpose flour, baking powder, nutmeg, and salt. Fold the ingredients with light hands.
Add cranberries and fold them in the muffin batter.
Divide the mixture in the muffin tray equally.
Set it aside and prepare the streusel.
Mix sugar, flour, salt, and orange zest in a bowl.
Add butter to the mixture and mix it with your hands until you get a crumbly mixture.
Spread the crumbly streusel mixture on the top of the muffins.
Place the muffin tray in the oven and let it bake for 20 minutes.
Check the muffins by pressing their top. If it bounces back, then your muffins are ready.
You can store them for two days in an airtight container. Or place them in the fridge for two weeks to use.