Wash and peel the carrot and radish. Wash green chillies and peel the ginger. Wipe and dry them up with a kitchen towel.
Cut the carrot and radish lengthwise into 2-inch long sticks. Cut the ginger into thick julienne. Slit the chillies lengthwise into two pieces. If you want a less spicy pickle, remove the chillies' seeds.
Heat a pan on low flame and add yellow mustard seeds, black mustard seeds, cumin seeds, coriander seeds, carom seeds, fenugreek seeds, aniseeds and black peppercorns. Roast them on a medium flame for 2-3 minutes until they smell aromatic.
Let the spices cool down completely and transfer them to a grinder. Grind them coarsely. Keep it aside.
Heat mustard oil in a kadhai or pan until smoking hot. Add hing and chopped vegetables. Mix it well and saute on medium-high flame for 2 minutes. Do not overcook the vegetables. It should have a bite, and the colour and texture should be intact.
Add turmeric powder, Kashmiri chilli powder, 1 ½ tablespoons of ground spices, onion seeds and salt. Mix them well and turn off the flame.
Add vinegar and mix it well. Let it cool down completely, and enjoy it with your favourite roti or parantha.
Store it in an airtight container. This pickle stays well for 2 days at room temperature. Store it in a fridge for a longer shelf life.
Instant gajar mooli mirch achar or pickle is ready to enjoy!