Preheat your oven to 350°F (175°C) and prepare a muffin tin by greasing it or lining it with paper liners.

In a large bowl, combine the all-purpose flour, granulated sugar, baking powder, and ground cinnamon.

In a separate bowl, whisk together the eggs and milk, then add the cranberry sauce until smooth.

Pour the wet ingredients into the dry ingredients; fold them together until just combined.

Fill each muffin cup about two-thirds full with the batter.

In a small bowl, mix the brown sugar, rolled oats, melted butter, and ground cinnamon until crumbly.

Sprinkle the crumb topping over each muffin evenly.

Bake for 20-25 minutes until golden brown and a toothpick comes out clean.

Let the muffins cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.