Butter or grease 12 wide-mouth 8-ounce mason jars.
To make the streusel, combine the pecans, butter, brown sugar, and spices in a small bowl.
To make the cake, whisk together the flour, baking powder, baking soda, and salt in a medium bowl.
Beat the butter and sugar with an electric mixer on medium-high until light and fluffy, 2 - 3 minutes. Beat in the eggs, vanilla, yogurt, and milk scraping down the sides of the bowl as necessary.
Reduce mixer speed to low and slowly add the flour mixture. Mix until thoroughly combined.
Spoon half the batter into the mason jars and top with half the streusel; repeat.
Place the jars on a baking sheet. Place on the center rack in the oven. Bake at 350 for 25 minutes or until an inserted toothpick comes out clean.
Place jars on a wire rack to cool.
Recipe by Premeditated Leftovers™ at https://premeditatedleftovers.com/?p=41189