Banana Bread Pecan Upside Down Cake

1 Preheat the oven to 350 F and place a rack in the middle of the oven. A place a rack with a sheet pan one level below to catch any drips.
Pecan Upside Down topping
3 Grease an 9" x 9" square metal pan with a bit of butter and then line it with a rectangle of parchment paper that goes down one side, across the bottom and up the other side.
4 Roughly chop the pecans and sprinkle them over the bottom of the pan.
5 In a small pot add in the brown sugar, maple syrup, butter, milk, and salt. Heat over medium low heat until melted, stir and cook until combined and just bubbling.
6 Turn off the heat and pour in the vanilla.
7 Pour the mixture all over the pecans and then put the pan on a kitchen towel into the fridge to firm and chill.
Banana Cake Batter
9 In a medium sauce pan, add in the butter, brown sugar, cinnamon and 3 of the sliced bananas (approximately 325 grams). Place the heat over medium low, and cook stirring regularly until the bananas start to soften  and the sugar has dissolved.
10 Once a bit soft and saucy, smush the bananas if needed with a fork. Then remove it from the heat and set aside to cool slightly.
11 In a medium mixing bowl add in the white sugar, eggs, salt, vanilla, yogurt and oil. Whisk to combine.
12 Pour in the caramelized banana smush and whisk again.
13 Sprinkle the flour over the surface of the wet ingredients and then the baking soda on top of the flour.
22 Before mixing together, peel and chop the last banana into 1/2″ chunks and add on top of the dry ingredients.
14 Use a rubber spatula to fold the wet into the dry ingredients.
Bake
16 Pour the batter over the pecan upside down mixture in the pan.
17 Bake the cake on the middle rack in the preheated oven for 20 minutes. After 20 minutes rotate the pan 180 degrees and bake for another 15-20 minutes until the edges are golden brown and a toothpick inserted in the center comes out clean.
18 Once baked, remove the pan from the oven and set aside to cool for 10 minutes. Not longer!!
19 After the 10 minutes have passed, place a serving plate or cutting board upside down over the pan.
20 Holding on to both the pan (careful it's hot) and the serving board, flip it over so the cake can fall out of the pan onto the board.
21 Leave it to cool for at least 10 minutes or a few hours before cutting into 9 squares and serving.