Bayam Ohitashi (Salad Bayam Jepang)

Bahan-bahan (4 porsi)

• ½ cup water
• 1 piece kombu (dried kelp)
• 1 Tbsp mirin
• 1 Tbsp usukuchi (light-colored) soy sauce
• 1 bunch spinach ((8 oz, 227 g))
• 1 tsp Diamond Crystal kosher salt
• katsuobushi (dried bonito flakes) ((skip for vegan/vegetarian))
• toasted white sesame seeds