1. Place rack in lower third of oven; preheat oven to 350ºF. Line an 8-inch baking pan with heavy-duty aluminum foil, leaving a 2-inch overhang on 2 opposite sides.
2. Combine butter and chocolate in a heatproof bowl and set over a pan of barely simmering water. Let stand, stirring occasionally, until almost melted. Remove bowl from pan, whisk until smooth and cool until warm.
3. Combine flour, baking powder and salt in a small bowl. Stir sugar into warm chocolate mixture. Add eggs one at a time, beating well after each. Mix in vanilla; fold in flour mixture. Spread batter in pan. Bake until just set in center, 30 to 35 minutes. Let cool completely in pan on wire rack.
4. Freeze pan for 30 minutes. Lift brownies out of pan using the overhanging foil; place on a cutting board. Use a 2 1/4-inch heart-shaped cookie cutter to make 9 brownies.
5. Place Candy Melts in a heatproof bowl over a pan of simmering water. Remove pan from heat, keeping bowl over water; stir until completely melted. Keep bowl over water as you work. Dip end of a lollipop stick into candy coating and insert into pointed end of a brownie. Place on a baking sheet. Repeat with remaining sticks and brownies. Place baking sheet in freezer for 10 minutes.
6. Carefully dip each brownie entirely or halfway into candy coating. Rotate stick, tapping it gently, allowing excess to drip off, or drizzle with coating. Apply decorations, if desired. Stand pops in Styrofoam.