01 - Preheat oven to 350°F. Grease and line a 9x5-inch loaf pan with parchment paper.
02 - Whisk together flour, baking powder, baking soda, salt, cinnamon, and nutmeg in a medium bowl.
03 - In a large bowl, beat softened butter and sugar with an electric mixer or whisk until light and fluffy, about 2 minutes.
04 - Beat eggs in one at a time. Mix in ricotta, milk, vanilla extract, and lemon zest (if using) until fully combined.
05 - Gradually add dry ingredients to wet ingredients, gently mixing until just incorporated. Avoid overmixing.
06 - Gently fold diced apples into batter until evenly distributed.
07 - Scrape batter into prepared loaf pan. Mix turbinado sugar and cinnamon for the topping, sprinkle evenly over the batter.
08 - Bake for 50 to 60 minutes, until a toothpick inserted in the center emerges clean.
09 - Allow bread to cool in pan for 10 minutes, then transfer to wire rack to cool completely before slicing.