Braised Short Rib Shepherd's Pie - Hummingbird Thyme

Ingredients

• 5 lb Beef Short Ribs
• 2 tbsp. EVOO
• 2 Small onions, trimmed and quartered (leave unpeeled)
• 1 Handful fresh thyme sprigs
• 1 Handful fresh rosemary sprigs
• 1 1/4 c Beef Broth (low sodium recommended)
• 1/2 c Dry white wine
• 1 1/4 c H2O
• 3 lb Russet Potatoes (about 6 medium)
• 1 1/2 Salt (Or, or to taste)
• 3/4 c Whole milk (we used 2%)
• 5 Medium Carrots, cut into 1/4" sliced
• 1/4 c Flour
• 2 tbsp. Unsalted Butter
• 1 1/2 lb Baby Spinach
• 1/2 Medium Onion, diced
• 2 tbsp. AP Flour
• 1 1/8 c (1 cup plus 2 TBSP) milk, warmed
• 2 tbsp. Grated Parmeggiano Reggiano Cheese
• 1/2 tsp. Salt
• 1 Pinch, freshly grated nutmeg