Apple cinnamon coffee cake

My mom has been baking this coffee cake for years, and each time it's like a new experience in your mouth. It's dense and caky at the same time, and the cinnamon adds a smidgen of autumn-ness. It's a simple recipe that begs to be made over and over throughout the cold months!

For the batter:

3 cups flour
1 1/2 cups sugar
2 teaspoons vanilla
1 1/2 teaspoons baking powder
1 1/2 teaspoons baking soda
1 teaspoon salt
2 eggs
2 cups plain yogurt
1 stick butter
2 green apples, peeled, cored, and thinly sliced (~1/4 centimeter thick)

For the swirlies: 

3/4 cup brown sugar
1 tablespoon cinnamon


Preheat oven to 375°F. In a small bowl, mix together with a fork the brown sugar and cinnamon. Set aside.

In a large microwavable bowl, melt the butter until soft. Add sugar first, then eggs, vanilla, baking powder and soda, yogurt, and salt. Once mixed, add the flour in batches, making sure to stir between additions.

Butter and flour a large bundt pan. Pour in half of the batter and sprinkle half of the swirlies mixture over it. Using a fork, push in swirlies to integrate them into the batter. Place half of the apple slices over the batter. Repeat with the second half of the batter, sprinkling almost all of the swirlies (leave ~2 tablespoons) over the top and then place the remaining apple slices on top. Sprinkle the remaining swirlies over the apple slices. Bake for about 40 minutes, or until knife comes out clean when inserted into cake. Eat it right out of the oven, or let cool and refrigerate for days!