1. In a large bowl, sift together flour, salt, and baking powder. Set aside.

2. In bowl of electric mixer fitted with the paddle attachment, cream together butter and sugar on medium until fluffy, about 5 minutes. Beat in egg and vanilla until incorporated.

3. Gradually add flour mixture on low until combined. Wrap dough in plastic; chill 1 hour.

4. Heat oven to 325 degrees. On a well-floured surface, roll out dough to 3/16 inch thick. Cut out 2 1/2-inch rounds. Use smaller cutters to cut hearts from rounds. (If desired, save and bake heart cutouts.) Transfer 8 cookies to an ungreased cookie sheet. Press 1 lollipop stick under each cookie. Place small hearts on same cookie sheet. Chill until firm, 15 to 30 minutes. Bake 8 to 12 minutes, until firm but not browned. Transfer cookies on pan to wire rack to cool, about 20 minutes. Repeat until all dough is used. Leave cooled heart pops on ungreased cookie sheet. Set aside.

5. Combine 1/2 cup corn syrup, 1 cup sugar, and 1/2 cup water in heavy 2-quart saucepan. Stir over medium heat, until sugar has dissolved. Increase heat to medium high; boil until mixture reaches 300 degrees on a candy thermometer, 25 to 35 minutes.

6. Remove from heat, and stir in flavored oil. Quickly pour mixture into 2 small heatproof bowls. Add food coloring to each; stir to combine. Pour into each empty heart. Make candy mixture again as in Step 5 with remaining ingredients and 1/2 cup water. Fill remaining cookies. Let set until hard, 10 to 20 minutes. Transfer in single layers to airtight containers. If humid, refrigerate.