Preheat oven to 400°F. Spray a 12-count muffin pan with baking spray or line with paper liners.
Whisk flour, granulated sugar, baking powder, cinnamon, and salt in a large bowl until combined.
2 cups (282g) all-purpose flour, 3/4 cup (150g) granulated sugar, 2 teaspoons baking powder, 1/2 teaspoon ground cinnamon, 1/2 teaspoon salt
Whisk milk, oil, eggs, and vanilla extract in a separate bowl.
3/4 cup milk, 1/2 cup vegetable oil, 2 large eggs, 1 teaspoon vanilla extract
Add wet ingredients to dry ingredients. Stir just until combined.
Add cranberry sauce and gently swirl into batter, but do not fully mix together.
1 cup cranberry sauce
Divide batter evenly between prepared muffin cups, filling them to top.
Bake for 18-20 minutes until golden brown.