Mussels with Tomato, Saffron, and Fennel

Ingredients

• 1/2 tsp saffron threads
• 1/2 cup hot water (not boiling)
• 1 Tbsp extra-virgin olive oil
• 2 shallots (finely sliced)
• 3 garlic cloves (peeled and crushed)
• 1 fennel bulb (finely sliced, fronds reserved)
• 1/4 tsp salt (divided)
• 1/2 cup white wine
• 1/2 cup low sodium vegetable stock
• 14 1/2 oz can no-salt-added diced tomatoes
• 1 lb farmed mussels (scrubbed, beards removed)
• 2 Tbsp chopped parsley
• 1 or 2 lemon wedges (for serving)