Discard any bruised outer leaves from the cabbage. Remove the leaves from the core and tear into rough pieces, discarding the tough central stems.

Heat the oil in a large saute pan over medium heat. Add the garlic and saute until it just starts to color, about 2 minutes. Add the speck and stir to coat in the oil. Add the cabbage, season with salt, toss to combine, and add the stock. Simmer until the cabbage leaves are just tender, about 4 minutes. Stir in the lemon juice just before serving.