Fragrant, floral grapefruit shines in this ultra-simple tart
For the filling:
3/4 cup (5 1/4 ounces) sugar
3 large eggs plus 4 large yolks
1 tablespoon cornstarch
1/2 teaspoon table salt
1 tablespoon ruby red grapefruit zest plus 1 cup juice (2 large grapefruits)
3 tablespoons lemon juice
5 tablespoons unsalted butter, chilled, cut into 10 pieces
6 drops red liquid food coloring
For the topping:
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