Halve the peppers lengthways, remove the stones and stem. Flatten each half lightly by hand. Then place with the skin facing up on a baking sheet lined with aluminum foil. Put this about 7cm under the grill in the oven and cook for 12-15 minutes until the skin is completely black. Put the peppers in a paper or foil bag, seal it tightly and allow the peppers to evaporate for 10-15 minutes. Take out and remove the burned skin.
Arrange the peppers nicely on a decorative plate. Spread the garlic evenly over the peppers and drizzle with olive oil and lemon juice. Sprinkle with salt and pepper. Let the vegetables rest for 15 minutes so that their full aroma can develop.
Just before serving, sprinkle with basil and garnish with the nasturtium flowers.