Make candy heart topper. Two days in advance, melt 2.5 oz. white Candy Melts Candy according to package directions. Place largest heart cutter from set in non-stick cookie pan. Use finger to lightly coat inside of cutter edge with solid vegetable shortening. Place third smallest (2 1/2 in.) heart cutter into center of largest heart. Use finger to lightly coat inner and outer edges of third smallest heart cutter with solid vegetable shortening.
Pour melted candy into large cutter, 3/4 full, leaving small cutter area open. Tap gently to smooth. Sprinkle with white nonpareils. Chill until firm, about 15 minutes. Gently remove both cutters.
Bend lollipop stick to follow curve of heart topper, leaving 3 in. straight to insert in cake. Use melted white candy in cut decorating bag to attach stick to back of topper. Chill until firm, about 3 to 5 minutes.