Heat a large grill pan and toast the brioche slices, turning once. Spread each toasted slice with butter and set aside.
Toss the berries in a bowl with the honey, lemon juice, and salt. Put them onto a sheet pan and roast for 5 minutes. Mash the cooked berries with a fork until spreading consistency. Spoon the warm berries over the brioche toast or let cool to room temperature. Berry mixture can be refrigerated for 1 week.