Whisk ricotta cheese and 1/2 cup sugar in a medium bowl until smooth and creamy. Stir in orange zest and vanilla bean paste. Cover and chill.
Sift flour and baking powder together into a large bowl and set aside.
In another bowl, whisk eggs and 3/4 cup sugar until blended. Add milk, melted butter, salt, and lemon zest; mix until smooth.
Gradually fold dry ingredients into wet mixture in 2 to 3 additions until a soft, cohesive dough forms. Finish mixing by hand, adding extra flour if sticky.
Cover dough and refrigerate for 15 minutes to firm. Preheat oven to 175°C (350°F). Line two baking sheets with parchment paper.
Divide dough into two logs, cut each into about 44 equal pieces, shape each into a smooth ball, and place on sheets spaced 2.5 cm (1 inch) apart. Flatten slightly.
Bake one tray for 10 minutes, rotating halfway, until bottoms are golden and tops are pale. Repeat with second tray.
While warm, cut a small circle from the flat side of each cookie and scoop out a cavity without puncturing through.
Pair cookies of similar size to form peach halves for assembly.
In a small bowl, mix rum or peach juice with food coloring and 1 tablespoon water. Place granulated sugar in a shallow bowl for coating.
Pipe or spoon about 1 teaspoon of ricotta mixture into each cavity. Press two halves together, removing excess filling.
Brush assembled cookies lightly with colored liquid, roll in granulated sugar, and place on a platter.
Cover assembled cookies with plastic wrap and chill for several hours to set filling and meld flavors.
Before serving, garnish each cookie with a mint leaf and allow them to stand at room temperature for 10-15 minutes.