Baked eggs with creamed spinach and Gruyère toasts - 9Kitchen

Ingredients

• 2 tbsp olive oil
• 20 gm butter
• 2 leeks, trimmed and thinly sliced
• 1 clove garlic, finely chopped
• 2 bunches English spinach, trimmed and washed
• 80 ml (1/3 cup) pouring cream
• Pinch freshly grated nutmeg
• 4 eggs, at room temperature
• 1 tsp tarragon vinegar
• 175 gm Gruyère, coarsely grated
• 160 gm (2/3 cup) crème fraîche
• 1 tsp Dijon mustard
• Thickly sliced sourdough bread