Step 1

Preheat the oven to 425ºF with the cast iron skillet inside, so it can preheat with the oven.

Step 2

Zest the lemon (you'll need about 1 tsp), then squeeze about 1 Tbsp of juice.

Step 3

In a large bowl, stir together the cornmeal, flour, sugar, baking powder, salt, and the lemon zest. Use your hands to massage the lemon zest into the dry mixture a bit to help release the flavorful oils.

Step 4

In a separate bowl, whisk together the milk, oil, egg, and 1 Tbsp lemon juice. Pour the whisked wet ingredients into the bowl with the dry ingredients. Stir just until the dry mixture is completely moistened. A few lumps are okay.

Step 5

Carefully remove the hot skillet from the oven. Add 1 Tbsp butter to the hot skillet and use a brush to spread the melted butter up the sides of the skillet.

Step 6

Pour the prepared cornbread batter into the hot skillet. Sprinkle the frozen blueberries over top (no need to thaw), then push them down into the batter with your fingers.

Step 7

Carefully return the skillet to the hot oven. Bake the cornbread for 20-25 minutes, or until the top and sides are deep golden brown and a toothpick inserted into the center comes out clean. Cool slightly, then slice into 8 pieces and serve.