01 - Preheat oven to 375°F. Line a 12-cup muffin tin with paper liners or lightly grease each cavity.
02 - In a large bowl, whisk together flour, granulated sugar, baking powder, baking soda, and salt until well blended.
03 - In a separate medium bowl, whisk ricotta cheese, eggs, milk, vegetable oil, and vanilla extract until smooth and creamy.
04 - Pour the wet mixture into the bowl with dry ingredients. Stir gently with a rubber spatula until just combined. Avoid overmixing.
05 - Fold in 3/4 cup of the chopped walnuts, reserving the remainder for topping.
06 - Divide batter evenly among muffin cups. Sprinkle with reserved walnuts and demerara sugar.
07 - Bake for 18 to 22 minutes, until muffins are golden and a toothpick inserted into the center emerges clean.
08 - Allow muffins to rest in the tin for 5 minutes. Transfer to a wire rack to cool completely.