Place the butter in a skillet on the stove over medium heat. Once the butter is melted and warm, add in the shallots and sautée for 5 minutes, until softened and turning golden brown. Add in the peas and continue to sautée for another 2 minutes, until they start to deepen in colour.
Blend the eggs, marscapone, thyme and salt with a regular or immersion blender until smooth. Pour it into a bowl and mix in the ham, peas and shallots until evenly combined.
Spoon into 18 greased muffin liners or pour into a greased casserole dish. Bake until eggs are set and golden brown on top. The muffins will probably take 20-30 minutes whereas the casserole format will take around 40-45 minutes.
Recipe by Love from the Land at https://www.lovefromtheland.com/ham-pea-frittata/