Groupon is offering $50 coupons for dinner at Bonsoiree Cafe & Delicacies for $20 at its site today. The Logan Square BYOB (with a $5 corkage fee per bottle) known for its “underground” Saturday-night dinners no longer has an a la carte menu, instead offering prix fixe tasting menus of 5, 7, or 13 courses ($50, $85, and $150, each with optional upgrades). The Groupon offer’s restricted to one coupon per table, Tuesday-Thursday, and must be redeemed within a year. There are sample menus and more info on the restaurant and the Saturday-night dinner here.