Preheat the oven at 180°C.

Grease a flat ovenproof pan with some of the olive oil.

Clean portobello mushrooms with a mushroom brush and remove the stems. Don't wash the mushrooms because they absorb water and get soggy.

Place chopped garlic, ginger and sambal olek in a mortar and grind into a smooth paste.

Transfer paste to a bowl, add lemon juice and rest of the olive oil. Mix well.

Place portobello mushrooms upside down in the pan and spread the spice paste evenly on the gills.

Bake in the oven for about 25 minutes.

Take mushrooms out of the oven, top with chopped coriander and some black pepper and serve immediately.