Empanadillas Gallegas

Cut tomatoes in half crosswise (not through core). Place a box grater in a large bowl. Grate tomatoes, cut side against the coarse side of the grater, until only skin remains; discard skin. You should have about 2 1/2 cups of grated tomatoes with juices.

In a large skillet, heat grapeseed and olive oils over medium heat. Add onions and cook, stirring often, until golden brown, adding more oil if onions are sticking, about 15 minutes. Form a well in center of the onions. Add the garlic to well and cook, stirring often, until slightly browned, about 2 minutes. Mix garlic into onions.

Add grated tomato and cook, stirring occasionally at first, then often during the last 15 minutes or so, until all the liquid has evaporated, mixture is reduced by 3/4 and is deeply red and caramelized, and you begin to see a separation of oil from the vegetables, 30 to 40 minutes. Add a splash of water to skillet to loosen any bits from the bottom of the pan and stir until evaporated. Let cool.

Set 3 tablespoons sofrito aside for the empanadillas. Divide remaining 3/4 cup sofrito into smaller portions in freezer-safe containers or an ice cube tray. Refrigerate or freeze for later use.