Make this batter with a combination of water and beer (preferably Miller Lite), for wonderfully crisp and light results.
2 cups flour
1 tsp. seasoning salt, such as Lawry's
1 tsp. paprika
1 12-oz. bottle light beer, such as Miller Lite
1 1⁄2 lbs. boneless skinless haddock filet, cut
into 2" × 3 1⁄2" pieces
4 slices marbled rye bread, halved crosswise
4–6 tbsp. butter
4 sprigs curly parsley
1 lemon, cut into wedges
1. Put flour, seasoning salt, and paprika into a large bowl and whisk to combine. Add beer and 1⁄2 cup water and whisk to make a smooth batter.
2. Pour the oil into a large heavy pot to a depth of 2" and heat over medium-high heat until the temperature registers 350° on a deep-fry thermometer. Lay the haddock on a paper towel–lined sheet pan in a single layer and pat dry. Working in batches, dip the haddock into the batter, shaking off some of the excess, and fry, turning occasionally, until cooked through and deep golden brown, about 5 minutes. Transfer the fried haddock to a rack as it is done.
3. Spread slices of rye with butter and spoon tartar sauce into 4 small cups. Divide haddock, rye, and tartar sauce between 4 large plates. Garnish plates with parsley and wedges of lemon and serve with German Coleslaw and German Potato Pancakes, if you like.