Line the bottom of your slow cooker with parchment paper (this will save you tons of time later with clean up!). Use a nonstick cooking spray and spray the side of your slow cooker.
Mix together the flour, cornmeal, sugar, salt, baking powder, and chili powder. In a separate bowl, mix together the egg, yogurt, milk, and butter. Combine the wet and dry ingredients and pour into the slow cooker. Sprinkle the jalapeños on top so that they evenly cover the cornbread mix. Cook on high for 1 to 1 1/2 hours, or low for 2 to 3 hours. Cook time will depend on the size of your slow cooker -- test the middle of the cornbread with a toothpick when you think it’s done. If it comes out dry, you’re set!
Take a serving plate the same size as your slow cooker and cover the top of the cooker with it. Flip the cooker quickly upside down and the cornbread should come right out!