Sweet and sour peppers (agrodolce di peperoni)

I was planning a meat-free menu for our Italian guests last weekend and browsing online for ideas for side dishes that would go with the main which was a baked risotto layered cake. I wanted to cook a dish with sweet peppers, and needed something hassle-free as the main was rather time-consuming.

Gennaro Contaldo's Agrodolce di peperoni on Good Food Channel looked easy and simple. Actually the Russians cook something similar with sweet peppers, only without anchovies. The Southern Russian cuisine is an amalgam of its southern and western neighbours, with the flavour influences from Moldova, Romania, Ukraine, and of course the Greek and Jewish communities from the Crimea.

I have slightly adapted the recipe, changing the method - cooking in the oven rather than fried - but the changes are minor (for a full recipe see the link above)

Sweet and sour peppers
Ingredients:
4tbsp olive oil (2 +2)
3 sweet peppers (red, orange and yellow), deseeded and cut into big slices
2 anchovies
1 clove of garlic
a handful of olives stuffed with garlic
1tbsp salted capers, rinsed
1tbsp caster sugar
2tbsp apple cider vinegar

Slice the peppers in half, deseed them and then slice each half into 3-4 pieces. Place the pepper in a deep ceramic dish or tray, drizzle with 2 tbsp of oil and place the dish in the oven preheated to 180C for about 25 minutes.
Heat 2tbsp of the olive oil in a frying pan, add the anchovies and garlic, and fry the garlic for about 3-4 minutes. Remove from the heat.
Add the sliced olives, capers, sugar and vinegar and mix into the peppers which should be cooked through by now. Leave the peppers in the oven, which has been turned off.
You can eat these peppers warm or cold. They make a tasty side dish, or a snack to go with cheese and bread.

You don't need salt, as the anchovies give it a salty taste. For a vegetarian version, omit the anchovies. I have searched online what's the best substitute for anchovies in vegetarian dishes, and there is a product called an umeboshi paste. I haven't used it myself, so cannot say what it tastes like, but apparently chefs use it in vegetarian recipes. I'll see if I can find it locally.
Does anyone use it, and would you recommend it?

I used the remains of Willy's Apple Cider Vinegar, which was one of the products in the January Degustabox. It's a tasty vinegar from the Herefordshire countryside.
It adds a lovely sour note to the peppers.
If you don't have this vinegar, any good apple cider vinegar will work well.