Against a backdrop of doleful news in the property and financial sectors, Ambassade de L'Ile, with Chef Jean-Christophe Ansanay-Alex, opened its door to diners in South Kensington, while the Helene Darroze at the Connaught started serving in Mayfair.
A third, Andaman with Chef Dieter Mueller, launches August 18 at the renovated St James's Hotel and Club in the heart of London's hedge-fund district.
All feature respected Michelin-starred chefs, luxury ingredients and prices among the highest in Britain &ndash ranging from about £65 to £95 for a basic fixed-price dinner (lunches are less pricey), and a la carte main dishes topping £30. That's before water, wine or frills such as caviar, foie gras or the post-meal cheese plate.
The menu by Mueller, who also cooks at gourmet destination Schlosshotel Lerbach near Koln, Germany, will describe Marco Polo's journey from the Mediterranean to Asia, with small plates priced at about £10 to £17.50 a piece.
Yet while the chefs and their backers are not complacent about the fiscal climate, they are cautiously optimistic.
"Business has already exceeded expectations," said Ansanay-Alex of Ambassade, where diners can sip watermelon gazpacho, with avocado puree and large Scottish langoustines or foie gras 'royale'.
Peter Harden, co-founder of Harden's restaurant guides, believes another reason restaurateurs are going for broke amid a faltering economy is that long-term effects may be less severe than in previous downturns.
He points out that because the restaurant-going population is getting younger, and women are delaying starting a family, there are more people with both the free time and disposable income.