►POTATOES: Fill a large saucepot halfway with water and add sea salt and potatoes. Bring to a boil over high heat, then reduce heat to medium-low and simmer for 20 minutes. Drain potatoes and pat dry.
►Melt butter in a large, wide skillet over medium-high heat. Add potatoes, season with sea salt and pepper, and stir to coat. Cook, stirring occasionally, until potatoes are crispy and golden brown, about 10 minutes. Remove from heat and garnish with flaky salt.
►CHEESE DIP: Warm olive oil in a large skillet over medium-low heat. Add shallot, jalapeño, bell pepper, garlic, and sea salt and cook until softened, about 5 minutes, stirring occasionally.
Increase heat to medium, add beer, and cook for 3 minutes. Reduce heat to low and add mascarpone.
►Stir until melted and creamy. Add cheddar and stir until melted and creamy. Taste and season additionally as necessary. Serve immediately with crispy potatoes.