Dinner

Homemade Fish Finger Sarnie with Sweet Potato Chips and Tartar Sauce Recipe

Name: Homemade Fish Finger Sarnie with Sweet Potato Chips and Tartar Sauce Recipe
Prep time: 15 min
Cook time: 35 min
Total time: 50 min
Cuisine: British
Ingredients: 300g skinless white fish fillet; 1 large egg, beaten; 50g cornflakes, blitzed or bashed into crumbs; 3 sweet potatoes, cut into chunky chips; 1 tbsp olive oil; Salt and pepper, to season; 2 tbsp light mayonnaise; 1 tbsp gherkins, finely chopped; 1 tsp capers, rinsed and chopped; Salt and pepper, to season; 4 small wholemeal buns; Small handful mixed salad leaves; 1 lemon, cut into wedges

ByCleo Brixton November 24, 2025November 24, 2025

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Introduction

This homemade fish finger sarnie is a delicious twist on a classic comfort food. Crispy cornflake-coated fish fillets paired with sweet potato chips and zesty tartare sauce make for a satisfying meal that’s easy to prepare and perfect for lunch or dinner.

The image shows a sandwich with three main layers on a white plate placed on a white marbled surface. The bottom layer is a whole wheat bun with some green arugula leaves on top. Above that, there is a thick, golden-brown crispy patty with a crunchy texture. The top layer is a dollop of white creamy sauce with small green specks, held together by the top half of the bun. Next to the sandwich on the plate are golden-brown thick-cut sweet potato fries, with a few lemon wedges placed in front of the sandwich. In the background, a white bowl with white sauce and a white spoon can be seen blurred. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

300g skinless white fish fillet
1 large egg, beaten
50g cornflakes, blitzed or bashed into crumbs
3 sweet potatoes, cut into chunky chips
1 tbsp olive oil
4 small wholemeal buns
Small handful mixed salad leaves
1 lemon, cut into wedges
2 tbsp light mayonnaise
1 tbsp gherkins
1 tsp capers, rinsed and chopped

Instructions

Step 1: Heat the oven to 200°C (180°C fan/gas mark 6). Cut the fish fillet into 4 equal-sized portions. Dip each piece into the beaten egg, then coat with the crushed cornflakes. Place the coated fish in the fridge to chill for 10 minutes.
Step 2: Toss the sweet potato chips in olive oil and a pinch of seasoning. Spread them out on a baking tray and bake for 20 minutes.
Step 3: While the chips are cooking, prepare the tartare sauce. Mix the light mayonnaise, chopped gherkins, capers, and a little seasoning together in a bowl. Set aside.
Step 4: Remove the sweet potato chips from the oven and turn them over. Arrange the fish fingers on the baking tray alongside the chips. Bake for an additional 15 minutes, turning the fish fingers halfway through.
Step 5: To assemble, add a few salad leaves to the bottom half of each wholemeal bun. Place a cooked fish finger on top, then add a dollop of tartare sauce. Serve with the sweet potato chips and lemon wedges for squeezing over.

Tips & Variations

For extra crunch, double coat the fish by dipping it in egg and cornflakes twice before chilling.
You can swap sweet potato chips for regular potato fries or oven-baked chips.
Add sliced tomatoes or pickled onions to the sarnie for additional flavor and texture.
Use gluten-free cornflakes to make this dish suitable for gluten intolerance.

Storage

Store any leftover fish fingers and sweet potato chips in an airtight container in the fridge for up to 2 days. Reheat in the oven at 180°C for 10–15 minutes to retain crispness. Avoid microwaving to prevent sogginess.

How to Serve

A close-up of a sandwich on a white plate with a white marbled background. The sandwich has three layers: a light brown whole grain bun on top, a thick, golden-brown crispy fried patty in the middle, and fresh green arugula leaves at the bottom. A dollop of white sauce is on top of the fried patty, and two lemon wedges rest on the plate next to the sandwich. To the right of the sandwich are golden sweet potato fries standing upright. In the blurred background, there is a white bowl with a white spoon inside. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I use frozen fish fillets for this recipe?

Yes, you can use frozen white fish fillets. Make sure to thaw them completely and pat them dry before coating with egg and cornflakes for the best results.

Is it possible to make this recipe dairy-free?

Absolutely. This recipe is naturally dairy-free since it uses light mayonnaise and no butter. Just check the mayonnaise label to ensure it doesn’t contain any dairy ingredients if you are sensitive.