Feta-and-Herb Phyllo Tart

sheets of thin 16-by-12-inch/40-by-30-centimeter phyllo pastry (about 200 grams)

tablespoons/45 grams unsalted butter, melted

scant cup/100 grams finely crumbled feta (3 1/2 ounces/100 grams)

lightly packed cups/50 grams finely grated pecorino Romano (1 1/2 ounces/45 grams)

tablespoons/5 grams roughly chopped parsley

tablespoons/5 grams roughly chopped tarragon leaves

tablespoons/5 grams roughly chopped mint leaves

eggs

cup/180 milliliters heavy cream (double cream)

cup/120 milliliters whole milk

Salt and black pepper