Thinly slice 10 garlic cloves. Pour 2 (28-ounce) cans whole tomatoes and their juices into a large, deep bowl. Squeeze and crush the tomatoes with your hands until a chunky sauce forms with pieces no bigger than 1 ½ inch.
Heat ½ cup olive oil in a large Dutch oven over medium-low heat until shimmering. Add the garlic and cook for 1 minute. Add ¼ teaspoon red pepper flakes if desired and cook, stirring occasionally, until the garlic is golden-brown and fragrant, 1 to 2 minutes.
Add ¼ cup double-concentrated tomato paste. Cook, stirring often, until the paste is darker in color and fragrant, 2 to 3 minutes. Add the tomatoes, 2 fresh basil sprigs, and ½ teaspoon kosher salt. Increase the heat to medium-high and bring to a simmer.
Reduce the heat to medium and simmer, stirring occasionally, until the tomatoes no longer taste acidic and the flavors meld, 25 to 30 minutes. Taste and season with more kosher salt as needed.