Baked Eggs with Chimichurri and Prosciutto

Name: Baked Eggs with Chimichurri and Prosciutto
Ingredients: 3 garlic cloves; 1 shallot; 1 cup (1 oz./30 g) fresh flat-leaf parsley leaves; 1 cup (1 oz./30 g) fresh cilantro leaves; 1/4 cup (1/4 oz./7 g) fresh oregano leaves; 1/2 cup (4 fl. oz./125 ml) extra-virgin olive oil; Juice of 2 limes; 2 Tbs. red wine vinegar; 1/4 tsp. salt, plus more, to taste; 1/4 tsp. red pepper flakes, plus more, to taste; Freshly ground black pepper, to taste; 1/2 pint (6 oz./185 g) cherry tomatoes, halved; Extra-virgin olive oil as needed, plus 1 Tbs.; 1/2 tsp. dried oregano; Salt and freshly ground black pepper, to taste; 4 thin slices prosciutto; 1 Tbs. unsalted butter; 1 large portobello mushroom, stemmed, brushed clean and sliced about 3/16 inch (5 mm) thick; 1 handful spinach; 1/4 cup (1 1/2 oz./45 g) crumbled feta cheese; 4 eggs (preferably free range and organic); Fresh oregano leaves for serving; Seeded toast for serving