In terms of "growing" time, garden cress holds the record for being one of the fastest-growing vegetable plants. It has a sharp, pungent flavor.
From Wikipedia: “Cress (Lepidium sativum), sometimes referred to as garden cress to distinguish it from similar plants also referred to as cress (from old Germanic cresso which means sharp, spicy), is a rather fast-growing, edible herb.
Garden cress is genetically related to watercress and mustard, sharing their peppery, tangy flavor and aroma. In some regions, garden cress is known as mustard and cress, garden pepper cress, pepperwort, pepper grass, or poor man's pepper. ...
When consumed raw, cress is a high-nutrient food containing substantial content of vitamins A, C and K and several dietary minerals.”
“Garden cress is added to soups, sandwiches and salads for its tangy flavor. It is also eaten as sprouts, and the fresh or dried seed pods can be used as a peppery seasoning (haloon). In the United Kingdom, cut cress shoots are commonly used in sandwiches with boiled eggs, mayonnaise and salt.”
“Raw cress is 89% water, 6% carbohydrates (including 1% dietary fiber), 3% protein and less than 1% fat. In a 100 gram amount, raw cress supplies 32 calories and numerous nutrients in significant content, including vitamin K, vitamin C and vitamin A. Among dietary minerals, manganese levels are high while several others, including potassium and magnesium, are in moderate content.”
“Garden cress, known as chandrashoor, and the seeds, known as aleev in Marathi, or halloon in India, are commonly used in the system of Ayurveda.”
Garden cress in agriculture:
“Garden cress is commercially grown in England, France, the Netherlands and Scandinavia.
Cultivation of garden cress is practical both on mass scales and on the individual scale. Garden cress is suitable for hydroponic cultivation and thrives in slightly alkaline water. In many local markets, the demand for hydroponically grown cress can exceed available supply, partially because cress leaves are not suitable for distribution in dried form, so they can only be partially preserved. Consumers commonly acquire cress as seeds or (in Europe) from markets as boxes of young live shoots.
Edible shoots are typically harvested in one to two weeks after planting, when they are 5–13 cm (2–5 in) tall.”