Heat the oven to 250°F and arrange a rack in the middle. Set a wire rack over a baking sheet; set aside.

Pour the oil into a Dutch oven or a large, heavy-bottomed pot. Heat over medium-high heat until it reaches 350°F on a deep-frying/candy thermometer.

Meanwhile, insert 2 toothpicks into the cut side of each piece of bratwurst, leaving about 1 1/4 inches of the toothpicks exposed on one side; set aside.

When the oil is almost ready (about 300°F), whisk the cornmeal, flour, baking powder, and salt together in a medium bowl. Whisk the beer, eggs, honey, and sugar together in a large bowl until combined and the sugar has dissolved. Add the cornmeal mixture to the beer mixture and stir with a rubber spatula until just combined. Pour some of the batter into a short, narrow container or drinking glass, leaving 1 inch of room at the top.

When the oil is ready, evenly dip a sausage piece into the glass of batter by holding the toothpicks and rotating the bratwurst as needed until it’s completely covered with batter.

Immediately place it in the hot oil. Repeat with 4 more bratwurst pieces. Fry, turning occasionally, until light golden brown all over, about 2 minutes. Using tongs, transfer the bratwurst dogs to the wire rack on the baking sheet and place in the oven.

Repeat with the remaining bratwurst pieces, working with 4 or 5 at a time, refilling the glass with batter as needed, and letting the oil return to 350°F between batches. (When you reach the last few pieces, you may need to tilt the glass sideways while rotating the bratwurst to evenly coat them with batter.) Serve immediately with mustard for dipping.