250g dried elbow pasta
40g butter, chopped
1/4 cup plain flour
3 cups milk
425g can tuna in oil, drained and flaked
1 cup frozen peas and corn, thawed
3 spring/green onions, sliced
1 1/2 cups finely grated cheddar cheese
juice of 1 lemon
3 cups mini pretzels, lightly broken with fingertips (some whole)
Preheat oven to 180C (160C fan forced). Grease a 2.5L capacity shallow ovenproof dish with cooking spray. Cook pasta in a large saucepan of boiling water according to packet directions. Drain well.
Meanwhile, melt butter in a large saucepan over medium heat until foamy. Add the flour and cook, stirring, for 1 min. Remove from heat and slowly whisk in milk until combined. Return to heat and cook, stirring, for 4-5 min until the sauce boils and thickens.
Remove from heat and stir in the pasta, tuna, vegetables, spring/green onions, 1 cup cheese and lemon juice. Season to taste. Pour mixture into prepared dish.
Toss pretzels with remaining cheese and 2 teaspoons olive oil in a bowl. Sprinkle evenly over the top of the tuna mornay. Bake in the oven for 20-25 min or until piping hot. Serve with mixed salad leaves.