Bittersweet Chocolate and Pear Cake

The flavors of this cake were very nice, but it did not come out how I expected it would. The recipe says that the pear and chocolate pieces will sink into the cake batter as it cooks. This did not happen with my cake. I did substitute Cup4Cup gluten-free flour for the regular flour the recipe calls for. I ended up with a pile of chocolate chunks on top of my cake. When it came out of the oven, I used a knife to smooth out the chocolate, but it was an inelegant solution at best. If I make this cake again, I would mix the pears and chocolate together before sprinkling on top of the batter.