Meanwhile, in a small saucepan, over low heat melt the white chocolate and butter together. Stir frequently to prevent burning. Cool slightly then add to the processed chickpeas and process everything for 1 to 2 minutes, or until it’s as smooth as possible (some texture from the chickpeas will remain). Add orange zest and flour and stir until just combined. Press into a buttered 8 x 8-inch (20 x 20 cm) cake pan. Bake for about 20 minutes or until the top and the edges start to brown.