Step 1

Preheat the oven to 430F/220C and line a high-sided (about 4cm or 1.5 inches) sheet pan or baking pan (roughly 9 x 13 inches or 23cm x 33cm) with baking paper.

Step 2

Spread all the chopped vegetables out on the lined sheet pan. Drizzle the olive oil over them, sprinkle over the dried herbs (if using) and toss well. Roast for around 15 minutes or until softened and starting to brown. Then turn the oven down to 375F/190C.

Step 3

Meanwhile, in a large jug or bowl, slowly blend some of the milk into the flour so that there are no lumps. Then whisk in the eggs, the rest of the milk, the mustard and the salt and pepper.

Step 4

When the vegetables are cooked, use a teaspoon to dot the pesto all over them evenly. Then sprinkle over the cheeses.

Step 5

Carefully pour the egg and milk mixture all over the top of the vegetables and cheese on the sheet pan. Then bake for around 25 minutes, or until the top is golden and the center no longer runny.

Step 6

Let cool for 10 minutes, then cut into 8 to 12 slices to serve.