Roasted Shallots with Mint Leaves and Grainy Mustard

I’d never had mint as a salad before I tried a dish very like this one at St. John, Fergus Henderson’s classic, modern/traditionalist restaurant near the Smithfield market (he’s married to Margot of Rochelle Canteen). It’s such a clever use of a very common ingredient, which grows like crazy in my garden. The shallots, too, are unexpectedly lovely: roasted and then separated into pale pink