Cut 8 oz. suet into 1-inch pieces. Place the pieces into a medium saucepan, and warm over medium-high heat. Stir until the suet melts completely.
Remove the pan from the heat. Mix in 1 cup crunchy peanut butter and 1 cup flour. Also, stir in 2 cups yellow cornmeal, 2 cups quick-cook rolled oats, and 1/3 cup sugar.
Line a sheet pan with parchment paper. Place heart-shaped cookie cutters on the parchment paper.
Pour the suet mixture into the cookie cutters. Place the sheet pan in the refrigerator for one to two hours to cool and harden the cakes.
Carefully remove the heart-shaped suet blocks from the cookie cutters. Use a wooden skewer to poke a hole through the suet cakes near the top edge. Feed a piece of twine through the hole. Hang the completed cakes from a tree branch.
Cut 4 oz. suet into 1-inch pieces. Melt the suet pieces over medium-high heat in a saucepan, stirring occasionally.
Remove the pan from the heat. Mix into the melted suet 2 cups unflavored breadcrumbs, 3 cored and chopped apples, 1 cup each unsalted nuts, raisins, crunchy peanut butter, wild birdseed, and white sugar, 1/2 cup flour, and 1/4 cup yellow cornmeal. Stir until all is incorporated and forms a tight mass.
Allow the suet to cool enough until you can handle it. Use your hands to mold the mixture into heart shapes. Place the hearts onto a parchment-lined baking sheet.
Freeze for one hour to set the mixture. Place the completed cakes on a fence post or into a suet feeder.