To prepare the sour cherry chutney, in a medium saucepan over medium heat, warm the olive oil. Add the onion and cook, stirring occasionally, until translucent. 

Add the cherries, brown sugar, vinegar and thyme and bring to a gentle simmer. Reduce the heat to low and cook, stirring occasionally, just until the chutney begins to thicken. Adjust the seasoning with salt and pepper.

To prepare the Manchego polenta cakes, in a saucepan over medium-high heat, bring the stock to a gentle simmer. Slowly stir in the polenta, whisking constantly. Continue to whisk until the polenta starts to thicken. Reduce the heat and cook, whisking, for 10 minutes more.

Remove the pan from the heat and stir in the butter and cheese. Adjust the seasoning with salt and pepper. Butter an 8-inch square pan. Pour the polenta into the pan and let cool, then cut into 1/2-inch squares.

To prepare the fried leeks, in a bowl, soak the leek slices in the milk for 10 minutes. Drain the leek slices and pat dry with paper towels, then toss with the seasoned flour.

In a pot, pour in oil and heat to 375°F on a deep-frying thermometer. Working in small batches, add the leek slices to the hot oil and fry until crispy. Transfer to a paper towel–lined plate to drain and sprinkle with salt.

To prepare the duck, preheat the oven to 400°F.

Using a sharp knife, hold it at a 90-degree angle and cut slits diagonally along the skin of the breast, making an incision every 1 inch. This is called scoring the breast and is necessary to let the skin release its fat during the cooking process so it can become crispy.

Now start the rendering process: Season the duck generously with salt and pepper. Place the duck, skin side down, in a heavy ovenproof fry pan over low heat. After a few minutes, you should see the skin begin to release fat. After 5 minutes, you will see a lot of fat rendering out. This is exactly what you want. This process of rendering will take 10 to 20 minutes, depending on the thickness of the skin. The skin is finished rendering when it is very brown and crisp to the touch. 

Flip the duck over, transfer the pan to the oven and roast until an instant-read thermometer inserted into the center of the duck registers 125°F, 5 to 7 minutes for medium-rare. 

Transfer the duck to a cutting board and let rest for 3 minutes, then thinly slice on a bias, or diagonally, through the breast.

To serve, top each polenta cake with a slice of crispy duck breast. Top with a spoonful of cherry chutney and sprinkle with fried leeks. Enjoy!