Preheat the oven to 350 degrees F and line an 8" x 8" cake pan with parchment paper.

Add the ingredients for the coffee cake, except for the chopped peach, to a blender. Blend until combined and smooth. Note: the cake batter will be very thick - this is normal. (Note: if you don't own a blender, you can prepare the batter as normal in a mixing bowl with a whisk or electric mixer).

Toss the chopped peach with 1 tsp coconut flour in a small bowl to ensure the chunks won't all sink to the bottom of the coffee cake. Fold the peaches into the coffee cake mixture.

Stir the ingredients for the pecan streusel topping in a small bowl until well-combined.

Pour 1/2 to 2/3 of the cake batter into the prepared cake pan and smooth into an even layer. Evenly spread 1/2 to 2/3 of the pecan topping mixture on top of the cake batter and use a knife to swirl it into the batter. Repeat for remaining cake batter and pecan topping.

Bake on the center rack of the preheated oven 30 to 35 minutes, until set up in the center and the edges are golden-brown. Turn off the oven and allow the cake to sit 5 to 8 minutes longer in the hot oven.

Remove cake from the oven and allow it to cool at least 30 minutes (the longer the better) before cutting into it. Enjoy!