Ingredients

• 1/2 stick (4 tablespoons) butter, at room temperature
• 1 cup sugar, plus 2 tablespoons for sprinkling
• 2 large eggs, room temperature
• 1 cup buttermilk, room temperature
• 1 teaspoon vanilla extract
• 1 cup all-purpose flour
• 1 cup cake flour
• 2 teaspoons baking soda
• 3/4 teaspoon kosher salt
• 1 1/2 tablespoons cinnamon, divided
• 1/2 teaspoon cardamom
• 1 granny smith or golden delicious apple, peeled and cored.
• 1/4 cup currants
• 3 very small apples, like crabapples, thinly sliced with seeds removed
• coarse sea salt, like maldon

for caramel glaze:

• 1/2 stick (4 tablespoons) butter
• 1/2 cup light brown sugar
• 2 tablespoons cream
• 1 teaspoon vanilla extract

Instructions

1. Prepare a 12-cup standard muffin tin by spraying it with nonstick cooking spray. You can also use paper muffin liners if you prefer. Preheat oven to 400 degrees.
2. In the bowl of a standing mixer, cream together butter and 1 cup sugar until pale and fluffy, about 3 minutes. Add eggs one at a time, beating well after each addition. Add buttermilk and vanilla, and beat until smooth.
3. In a separate bowl, whisk together both flours, baking soda, salt, 1/2 tablespoon cinnamon, and cardamom. Add to butter mixture and beat on lowest setting just until combined.
4. Chop half of the apple into 1/2" cubes. Use a box grater to coarsely grate the other half. Squeeze the grated apple between a few paper towels to remove excess moisture, then add chopped and grated apple to the mixing bowl. Add currants, and beat just until combined.
5. Divide batter evenly between the cups of the muffin tin. The cups should be almost filled to the top. Place 1 or 2 slices of crabapple on top of each muffin. Mix together remaining 2 tablespoons of sugar with 1 tablespoon cinnamon, and sprinkle all over the tops of the muffins.
6. Bake for 20 - 25 minutes, until tops of muffins spring back to the touch, and a toothpick inserted in center comes out clean. Allow to cool in pans for 10 minutes, then transfer muffins to a wire rack.
7. While the muffins are cooling, make the caramel glaze: In a heavy-bottom saucepan, melt the butter with the brown sugar. Whisk until smooth, then continue whisking while you add the cream. Whisk until the glaze is smooth and just comes to a boil. Add vanilla, then remove from heat.
8. Pour the warm glaze over the muffins and allow to set. Sprinkle with a few flakes of sea salt...  They're best eaten while warm!