Set a large pot of water over high heat. When the water is boiling, add enough salt so that the water tastes like the ocean, and reduce the heat so that the water is gently simmering. Add the kohlrabi, and cook them for 30-45 minutes, until they are easily pierced with a fork. When the kohlrabi are finished cooking, remove them from the pot using a slotted spoon and transfer them to a cutting board.

Using a paring knife, remove and discard the fibrous outer skin of the kohlrabi. Slice the remaining kohlrabi into bite-size pieces. Season the kohlrabi lightly with salt. Set the kohlrabi aside for a moment.

Set a medium-sized pot over medium heat and add the olive oil, along with the garlic, chili flakes, thyme, and lemon zest. When the oil begins to bubble and sizzle, reduce the heat to low, and cook for 3 minutes. Remove the pot from the heat and allow the flavors to steep for 15 minutes. Add the juice of 1 lemon, and stir to combine. Pour the oil through a fine mesh strainer. Reserve the oil and discard the rest.

Transfer the kohlrabi to an airtight container, along with the oil. Allow the kohlrabi to marinate in the refrigerator for 48 hours. As long as the kohlrabi is stored in the refrigerator, fully submerged underneath the oil, it will keep for two weeks.

When you are ready to serve the marinated kohlrabi, the oil may be congealed. Allow the kohlrabi to sit at room temperature until the oil becomes translucent again. The marinated kohlrabi is best enjoyed as part of an antipasti platter, served alongside some combination of bread, olives, cheeses, salumi, sundried tomatoes, and roasted peppers.