Preheat the oven to 350 degrees F. Grease an 8 or 9-inch ovenproof skillet or baking pan. In a large bowl, toss the blueberries with 1/2 cup sugar, lemon juice, and salt. In a separate bowl, mix the crumbs with the melted butter and 3 tablespoons sugar.Layer half the blueberries into the prepared skillet. Top with one-third of the bread crumb mixture. Layer the remaining blueberries over the top. Finish with the remaining crumbs. Transfer the skillet to the oven and bake for 45-50 minutes, until the top is golden and the edges are bubbling. Remove the skillet from the oven and let it cool for 10 minutes before serving the brown betty with ice cream or heavy cream.