Soften the butter for about 1 hour at room temperature. Arrange oven racks to divide the oven into thirds, and preheat to 350°F (175°C). Grease three 9x13-inch pans and line each with parchment paper, leaving an overhang.

Beat the almond paste with the softened butter until well combined. Add sugar and salt, and beat for about 5 minutes until fluffy. Add eggs and almond extract, and beat for 2 minutes. Stir in flour on low speed until no streaks remain.

Divide the batter into three bowls. Tint one with red food coloring and the other with green. Spread batter in thin, even layers in each pan. Bake for 10 to 14 minutes until tops look dry but not browned. Cool completely before proceeding.

Lift the green layer onto a cutting board and spread half of the apricot jam over it. Add the plain layer on top, spread remaining jam, and finish with the pink layer. Cover with parchment, place a sheet pan on top, and weigh down with cans. Refrigerate for at least 2 hours.

Melt chocolate chips in the microwave in 30-second bursts, stirring until smooth. Trim edges of the layered cake, spread chocolate over the top and sides, and chill for about 30 minutes until set.

Use a warm, dry knife to cut the bars into 2-inch pieces. Arrange the bars on a plate or tray for serving.