1cup (112g)pecan halves, (you can also use a mix of walnut and pecans)
1 /2cuprolled oats
1/2cup (56g)whole wheat pastry flour or all purpose flour
3/4teaspoonkosher salt
1/4teaspoonginger
1/2teaspooncardamom
1/2teaspoonpumpkin pie spice or cinnamon
1tsp.baking soda
½tsp.baking powder
1/2cup (90g)grapeseed oil, or unsalted butter, melted (or browned!)
1/4cup (50g)light brown sugar
1/4cup (50g)white sugar
2large eggs, , room temperature
1tsp.vanilla extract
½cupplain whole-milk Greek yogurt, , room temperature
1-2tablespoonsturbinado sugar , (or more white sugar), for topping
Instructions
Toast the Pecans:
This can be done up to a week in advance.Preheat oven to 375. Place pecans on a baking sheet. Bake until light brown and fragrant, about 6-7 minutes. Set aside to let cool.
Make the Cake
Preheat oven to 350 and prepare a 9x9 or 8x8 metal pan by spraying it with oil and lining with parchment paper.
Cut the apples into very thin slices (see example above).
Place pecans and oats in a food processor. Grind until as fine as possible, but not turning into pecan butter. If using a large food processor, add in remaining dry ingredients (flour, salt, ginger, cardamom, cinnamon/pumpkin pie spice, baking powder, and baking soda) and pulse to combine. If using a small food processor, do this in a large bowl instead.
In a large mixing bowl, add melted butter* or grapeseed oil, white sugar, light brown sugar, eggs, and vanilla extract. Using a whisk, vigorously whisk until lighter in color and the batter has some air bubbles, about 1 minute.
In increments, add and stir in pecan mixture to the bowl. Stir until combined.
Add in yogurt and stir until fully integrated into the batter. Pour batter into prepared pan.
Gently add apple slices on top- see my notes above for tips and tricks. Sprinkle with turbinado sugar.
Bake until the center is set and the edges of the cake are coming away from the pan, about 35-40 minutes. From my experience, the edges will come away more quickly then the center, so be sure to look at the center too!